Trip from Southmayd, TX to San Antonio, TX

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Compiled and reviewed by the US Trip Planner planning team at COD Solutions Oy · Last reviewed Oct 23, 2026 · Editorial standards

Drive Time

6h 13m

Distance

339.2 mi

546 km

Drive Score

9/10

Great drive

Same Day?

Yes, doable

Fuel Cost

$51

one way

EV Charging

Unknown

Best Time to Leave

Save up to 38 min

4 AM

6h 1m ★

6 AM

6h 14m

8 AM

6h 39m

10 AM

6h 23m

12 PM

6h 20m

3 PM

6h 24m

5 PM

6h 38m

8 PM

6h 6m

Estimated drive times based on typical traffic patterns. Actual times may vary with weather, construction, and real-time conditions.

Best Time

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Southmayd, TX

Jeff Stapleton

San Antonio, TX

Wikimedia Commons

Trip Overview

Southmayd, TX to San Antonio, TX is 339.2 miles and takes about 6h 13m via Purple Heart Trail and I 35, with a fuel budget near $49 and enough daylight to finish in a day. This drive stays within Texas, traversing the Great Plains region for both departure and arrival. You'll find a mix of highway and surface roads on this trip, making for a varied driving experience. It's a straightforward path that can easily be completed in a single day, allowing for flexibility in your schedule.

Trip Pace

Same-day drive is realistic

A same-day return is possible, but it will make for a full day on the road.

Break Rhythm

1 planned break

Plan on a short reset every 3 to 4 hours to stay fresh behind the wheel.

Midpoint

169.6 miles from Southmayd, TX

A natural place for your longest stop of the day , about 3h 9m into the drive .

Main Roads

Road	Distance	Duration
Purple Heart Trail	99.6 mi	1h 46m
South R L Thornton Freeway	89.9 mi	1h 32m
I 35	55.8 mi	58m
Dallas North Tollway	29.6 mi	32m
State Highway 289	25.3 mi	30m
North Pan Am Expressway	17 mi	20m
North Jack Kultgen Expressway	6.6 mi	7m
State Highway 56	4.1 mi	4m

Longest stretch: Purple Heart Trail — 99.6 mi, about 1h 46m

Traffic on I-35

Hour-of-day weekday pattern from 104 FHWA count stations on your route.

Peak

3 PM

~4,070 veh/hr typical · worst 4,856

Quietest

2 AM

~706 veh/hr

Peak-to-quiet ratio

5.8×

busier at peak than in the quiet hours

12a 6a noon 6p 11p

Averaged across 104 weeks of 2023 FHWA Travel Monitoring Analysis System data. Weekday hours only (Mon–Fri).

Turn-by-Turn Driving Directions

Step-by-step road directions between Southmayd, TX and San Antonio, TX.

Start on Belknap Road

386 ft · 19 sec · Belknap Road

Turn left onto McElroy Street

0.3 mi · 1 min · McElroy Street

Turn left onto TX 56

4.1 mi · 4 min · State Highway 56

Turn slight right

0.4 mi · 1 min

Turn straight onto TX 289

25 mi · 30 min · State Highway 289

Use the straight lane.

Continue on TX 289

3.0 mi · 4 min · North Preston Road

Use the left / straight lanes.

Turn slight right

0.3 mi · 49 sec

Toward US 380

Keep slight right at fork

233 ft · 11 sec

Turn right onto West University Drive

0.2 mi · 19 sec · West University Drive

Keep slight left at fork

0.2 mi · 30 sec

Merge onto US 380

0.2 mi · 14 sec · West University Drive

Take the exit

0.2 mi · 17 sec

Toward Dallas North Tollway Use the slight right lane.

Continue on West University Drive

0.3 mi · 42 sec · West University Drive

Use the straight lane.

Turn left onto Dallas Parkway

0.5 mi · 42 sec · Dallas Parkway

Use the straight lane.

Take the ramp

0.2 mi · 24 sec

Toward DNT Toll South

Merge onto DNT

30 mi · 32 min · Dallas North Tollway

Use the straight / slight right lanes.

Keep slight right at fork

0.4 mi · 49 sec

Toward I 35E South Use the right lane.

Keep slight right at fork

329 ft · 8 sec

Toward I 35E South Use the slight left / slight right lanes.

Turn straight onto North Stemmons Freeway

0.1 mi · 12 sec · North Stemmons Freeway

Take the ramp

0.1 mi · 17 sec

Toward I 35E South

Merge onto I 35E

1.8 mi · 2 min · North Stemmons Freeway

Use the straight / slight right lanes.

Continue on I 35E

0.5 mi · 44 sec · South R L Thornton Freeway

Continue on I 35E

89 mi · 1 hr 31 min · South R L Thornton Freeway

Exit 426 Toward Dallas Zoo Use the straight / slight right lanes.

Continue on I 35; US 77

6.6 mi · 7 min · North Jack Kultgen Expressway

Use the straight / slight right lanes.

Continue on I 35

38 mi · 39 min · Purple Heart Trail

Use the straight / slight right lanes.

Keep slight left at fork onto I 35

56 mi · 58 min · I 35

Use the straight / slight right lanes.

Keep slight left at fork onto I 35; US 290

50 mi · 54 min · Purple Heart Trail

Toward 32nd Street, Dean Keeton Street Use the slight left lane.

Continue on I 35

1.7 mi · 1 min · Interstate Highway 35

Use the straight / slight right lanes.

Continue on I 35

12 mi · 12 min · Purple Heart Trail

Use the straight / slight right lanes.

Continue on I 35

10.0 mi · 11 min · North Pan Am Expressway

Use the straight / slight right lanes.

Keep slight left at fork onto I 35

6.4 mi · 8 min · North Pan Am Expressway

Toward I 35 South Use the straight / slight right lanes.

Keep slight left at fork onto I 35

0.6 mi · 41 sec · North Pan Am Expressway

Toward I 35 South: Lower Level, Laredo Use the slight left lane.

Take the exit

0.1 mi · 16 sec

Exit 157A Toward Lexington Avenue, Main Avenue, San Pedro Avenue Use the slight right lane.

Turn straight onto East Elmira Street

526 ft · 17 sec · East Elmira Street

Use the left / straight lanes.

Turn left onto North Main Avenue

0.2 mi · 18 sec · North Main Avenue

Use the left / straight lanes.

Enter roundabout onto Navarro Street

159 ft · 3 sec · Navarro Street

Continue on Navarro Street

111 ft · 2 sec · Navarro Street

Keep slight right at fork onto North Main Avenue

0.4 mi · 51 sec · North Main Avenue

Use the slight left / slight right lanes.

Turn right onto West Travis Street

222 ft · 10 sec · West Travis Street

Turn left onto North Flores Street

0.2 mi · 20 sec · North Flores Street

Continue on Military Plaza

392 ft · 15 sec · Military Plaza

Turn left onto Dolorosa Street

327 ft · 8 sec · Dolorosa Street

Arrive at destination

Dolorosa Street

Trip Plan

Given the 6h 13m estimated drive time, leaving Southmayd in the morning is your best bet to reach San Antonio comfortably within daylight. With only one recommended stop, you have plenty of flexibility to adjust your pace. The fuel cost is estimated at $49, so ensure your tank is full before you depart. Pay attention to the transition points between highway and surface roads; the longest stretch on the Purple Heart Trail is 99.6 miles, so plan your fuel and rest stops accordingly before hitting that longer segment.

Morning Departure

Start early — leave by 6-7 AM to arrive at a reasonable hour.

Evening Departure

This is a long drive — plan for a morning departure or consider splitting it into two days.

You can normally do this drive in one day.

Plan roughly 1 meaningful break for fuel, food, and rest.

The halfway point lands around 169.6 miles from Southmayd, TX, or about 3h 9m into the drive.

The longest continuous stretch on this route runs about 99.6 miles.

This is a comfortable same-day trip.

Departure

Before you leave

Start with fuel, water, and navigation already sorted so the first hour feels easy.

First stop

Around 75 miles or 1h 31m in

Use this first pause for coffee, a restroom break, and a quick traffic check ahead.

Halfway reset

Around 169.6 miles or 3h 9m in

This is the best place for your longest stop, a real meal, and a full fuel check.

Final approach

Final hour starts around 5h 5m

Traffic, exits, and arrival timing usually matter more near San Antonio, TX than in the middle of the route.

Before You Leave

Open the route before leaving Southmayd, TX so your first major turns are already loaded.

Leave with enough water and a charging cable within reach, not packed away.

Check your fuel range against the first long segment, especially if you are starting outside city service areas.

Day 1

Settle into the route from Southmayd, TX

This is one driving day of about 339.2 miles and 6h 13m.

Your first comfortable stop window is around 75 miles from Southmayd, TX.

This route can stay practical as a one-day drive if traffic stays reasonable.

Plan about 1 real break rather than only quick fuel stops.

The longest stretch is on Purple Heart Trail for about 99.6 miles.

Where to Stop

Rest stops, refuel points, and overnight suggestions along this route.

Mid-route town

Meal stop

Troy, TX

170 mi into the route

Best for: Lunch, fuel, and a longer reset

This sits close to the middle of the route, so it works well for the longest stop of the day.

Pacing Suggestions

Dallas, TX

Fuel and coffee

A short stop after about 75 miles helps settle the day before fatigue starts building.

Troy, TX

Meal break

The midpoint is around 169.6 miles from Southmayd, TX, which is a good place for a longer meal and fuel stop.

Before the longest stretch

Hours: 10 am–5 pm

+12106101160

Visit website

Place data sourced from public business listings. Hours and availability may vary.

Heads-up: tricky spots

5 of 28

5 decision points cluster between mile 34.1 and 338 — GPS handles the exact turns, but know they're coming. Your lane choice matters more than the turn itself.

34.1 mi into trip | ~44m in

Take the exit toward Dallas North Tollway

Exit ramp - move to the correct lane early. Lane positioning matters here

Use the slight right lane. Toward Dallas North Tollway

64.8 mi into trip | ~1h 19m in

Keep slight right at fork toward I 35E South

Highway fork - watch signs carefully. Lane positioning matters here

Use the right lane. Toward I 35E South

257.6 mi into trip | ~4h 41m in | I 35; US 290 / Purple Heart Trail

Keep slight left at fork onto I 35; US 290 / Purple Heart Trail toward 32nd Street, Dean Keeton Street

Highway fork - watch signs carefully. Lane positioning matters here. Multiple destination signs - pick the right one

Use the slight left lane. Toward 32nd Street, Dean Keeton Street

337.4 mi into trip | ~6h 10m in | I 35 / North Pan Am Expressway

Keep slight left at fork onto I 35 / North Pan Am Expressway toward I 35 South: Lower Level, Laredo

Highway fork - watch signs carefully. Lane positioning matters here. Multiple destination signs - pick the right one

Use the slight left lane. Toward I 35 South: Lower Level, Laredo

338 mi into trip | ~6h 11m in

Take the exit toward Lexington Avenue, Main Avenue, San Pedro Avenue

Exit ramp - move to the correct lane early. Lane positioning matters here. Multiple destination signs - pick the right one

Use the slight right lane. Exit 157A Toward Lexington Avenue, Main Avenue, San Pedro...

Fuel & Cost

Regular Gas

$50.92 one way

$101.84 round trip

$3.81/gal 25.4 MPG avg 119 kg CO₂

Fuel Type	$/gal	One Way	Round Trip
midgrade	$4.22	$56.34	$112.68
premium	$4.57	$60.96	$121.93
diesel	$6.28	$83.81	$167.62

Estimated Tolls: $2.37

Dallas North Tollway (29.6 mi) $2.37

Toll estimates based on average 2024-2025 rates. EZ-Pass/SunPass discounts may lower the actual cost.

Estimated Trip Cost (one way, 1 person)

Fuel

$51

Tolls

Meals

$25–$50

Total

$78–$103

Rough estimate based on US averages. Hotel $80–$140/night, meals $25–$50/day.

Estimated CO2 emission: 118.7 kg one way. Prices: EIA weekly data, 2026-10-19.

Driving Electric?

About $36 in charging · 1 stop · 66% less CO₂

Vehicle Type	kWh	Stops	DC Fast	Home Charge
Average EV	101.8	1	$35.62	$16.28
Efficient EV	84.8	0	$29.68	$13.57
EV Truck/SUV	135.7	1	$47.49	$21.71

Gas CO2

119 kg

EV CO2

40 kg (66% less)

Plan for 1 charging stop. A 30-minute DC fast charge mid-route should be enough to complete the trip comfortably.

DC fast charging avg $0.35/kWh. Home charging avg $0.16/kWh. US grid CO2: 0.39 kg/kWh.

Travel Intel

Current conditions at both ends of the drive.

Forecast as of Oct 19, 2026

Origin

Southmayd, TX

Late night in Southmayd on Friday

Local time

4:51 AM

CDT

Current temp

50°F

Mostly Cloudy

SE 5 mph 0% chance Live forecast

Destination

San Antonio, TX

Late night in San Antonio on Friday

Local time

4:51 AM

CDT

Current temp

55°F

Mostly Cloudy

NE 5 mph 0% chance Live forecast

57°F

Troy, TX

170 mi in

Seasonal Notes

Summer travel usually means heavier construction, hotter rest stops, and busier weekend traffic around major cities.

Winter travel shortens daylight, so a route that looks manageable on paper can feel much longer after dark.

Holiday weekends tend to make both departure and arrival windows slower than the raw route time suggests.

Time zone

Same local time

Origin and destination are on the same clock, so arrival timing is easier to judge at a glance.

Temperature spread

5 degrees warmer at arrival

A meaningful temperature swing is a good cue to rethink layers, water, and how soon you want to arrive.

Road read

6h 13m on the road

Start early — leave by 6-7 AM to arrive at a reasonable hour.

Weather data from the National Weather Service. Conditions may change; check closer to your travel date.

National Parks Near This Route

Worth a detour if your schedule allows.

Waco Mammoth National Monument

National Monument

Standing as tall as 14 feet and weighing 20,000 pounds, Columbian mammoths roamed across what is present-day Texas thousands of years ago. Today, the fossil specimens represent the nation's first and...

6 mi from route ~15 min detour Free near mile 152

View on nps.gov

San Antonio Missions National Historical Park

National Historical Park

Welcome to San Antonio Missions, a National Park Service site and the only UNESCO World Heritage Site in Texas. Each mission in the park is a center of community and has been since the early 1700s. Th...

9 mi from route ~22 min detour Free near mile 339.2

View on nps.gov

Park data from the National Park Service API. Alerts update every 2 hours.

What kind of drive is this?

About 60% of this 339.2-mile route is on highways. The longest continuous stretch you'll encounter is 99.6 miles on the Purple Heart Trail. Expect the transition from highway to surface roads to be noticeable as you navigate the 6h 13m drive. The prevalence of highway driving means you'll likely experience periods of steady cruising, interspersed with areas that have more frequent exits and local traffic.

60% highway — fuel and pacing are the main things to plan.

43 navigation steps total — most of the decisions cluster near the start and finish.

Longest single stretch: 99.6 mi on Purple Heart Trail.

How Hard Is This Drive?

8/10

This route mixes highway mileage with some local-road sections near the start or finish. This route has several spots where lane changes, forks, or exits need your full attention. The trickiest moment comes around 34.1 miles in.

Driving Effort 8/10

Demanding - plan breaks and stay ahead of the key maneuvers

Balances navigation complexity with total wheel time.

This is a demanding drive. With 28 significant decision points across 339.2 miles, you will need to stay alert - especially through interchange areas and urban stretches. Consider splitting it into segments if you are not comfortable with fast highway navigation.

Where does it get tricky?

The main spots that need attention: at 34.1 miles: Exit ramp - move to the correct lane early. Lane positioning matters here; at 64.8 miles: Highway fork - watch signs carefully. Lane positioning matters here; at 257.6 miles (I 35; US 290 / Purple Heart Trail): Highway fork - watch signs carefully. Lane positioning matters here. Multiple destination signs - pick the right one.

Elevation Profile

Mostly flat terrain

869 ft 564 ft

Total Climb

738 ft

Total Descent

822 ft

Highest Point

869 ft

~218 mi in

Elevation Range

305 ft

Towns Mentioned on Route Signs

Based on OSRM destination-sign hints, not a full list of every settlement the road passes.

Between Southmayd, TX and San Antonio, TX, road signs point toward Dallas North Tollway, Dnt Toll South and Dallas Zoo.

Dallas North Tollway

34.1 mi in | ~44m

Dnt Toll South

35 mi in | ~46m

Dallas Zoo

67.9 mi in | ~1h 24m | via I 35E

About the Cities

Arriving in San Antonio, TX

Full guide →

Founded 1718

San Antonio is the second largest city in the state of Texas and the 7th largest in the United States. It's the 24th largest metropolitan area in the country. Visited by more than 31 million annual visitors, San Antonio is a beautiful city at the axis of three different geological terrains: Hill Country, South Texas Plains and Prairie and Lakes. There's a lot to do in this city: fine art museums, historical missions and plenty of amusement parks in addition to great dining and lots of drinking. The culture and people are vibrant and interesting. San Antonio's downtown is one of the most lively in the nation.

Top landmarks

• Alamo Mission — historic place in San Antonio, Bexar County, Texas
• San Antonio Missions National Historical Park — historic district in San Antonio, Bexar County, Texas
• Fort Sam Houston — military base in San Antonio, Texas, United States

City content from Wikivoyage (CC BY-SA 4.0) and Wikidata (CC0).

Who Is This Route For?

Weekend Trip

Doable as a same-day drive at 6h 13m. Total distance: 339.2 miles.

Family Friendly

Moderate complexity with 1 natural rest stops along the way.

Solo Traveler

6h 13m drive, plan rest stops for pacing.

Frequently Asked Questions

The longest stretch is about 99.6 miles on Purple Heart Trail. The full list of main roads is in the Roads section above.

Expect about $2.37 in tolls one way, starting with Dallas North Tollway. Most Northeast and Midwest toll agencies accept E-ZPass; in the West and Texas, transponders like TxTag or FasTrak apply. If you do not have a transponder, cashless tolling plates will mail a bill to the vehicle's registered address — usually with a surcharge, so a rental-car toll pass is often cheaper than paying by mail.

Yes — we found about 31 rest areas or service plazas within a short detour of the route (from OpenStreetMap). See the Rest Stops tab under Nearby Places for locations and mile markers. Plan to stretch, use the bathroom, and top off fluids every 2–3 hours on longer drives.

It helps. This route has a higher-than-average number of complex decision points, which get harder in the dark. If the last hour of the trip is on surface roads or mountain grades, aim to arrive at San Antonio, TX before sunset when you can. Check the Trip Plan for departure windows that land you in daylight.

Only with planning. This is a long drive for kids — consider splitting it into two days rather than pushing through. Plan at least 1 meaningful breaks. There are 31 rest areas along the route for bathroom stops.

Yes — Waco Mammoth National Monument and San Antonio Missions National Historical Park. See the National Parks section for detour distances and tips on detours.

Not recommended in a single day. At 6.2 hours each way, a round trip means 12.5 hours of driving — that is an unsafe level of fatigue for most drivers. Plan at least one night at San Antonio, TX before the return drive.

How this page is built

Compiled by the US Trip Planner planning team at COD Solutions Oy from open government datasets — OSRM over OpenStreetMap for geometry, EIA for fuel prices, USGS 3DEP for elevation, NPS for national parks, and FHWA TMAS for hourly traffic volumes. See our methodology for refresh cadence and limitations.

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Explore more options from Southmayd, TX or browse trips ending in San Antonio, TX.

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Trip from Southmayd, TX to San Antonio, TX

Best Time to Leave

Trip Overview

Main Roads

Traffic on I-35

Turn-by-Turn Driving Directions

Trip Plan

Before You Leave

Where to Stop

Pacing Suggestions

Stops Along Your Drive

Bell County Northbound Rest Area

Service Plaza

Hill County Northbound Rest Area

Buc-ee's

Flying J Travel Center

Walburg Travel Center & Food Court

Love's Travel Stop

Petro Stopping Centers

Buc-ee's

Service Plaza

QuikTrip

TA

Flying J Travel Plaza

Pilot Travel Center

Hill County Southbound Rest Area

QuikTrip

Road Ranger

Marlstone Retail Center

Love's Travel Stop

Love's Travel Stop

Buc-ee's

Pilot Travel Center

TA

Service Plaza

Bell County Southbound Rest Area

QuikTrip

Love's Travel Stop

Pilot Travel Center

Service Plaza

Petro Stopping Centers

Pilot Travel Center

Spanish Governor's Palace

GO RIO San Antonio River Cruises

San Antonio | The Saga

Hemisfair

San Antonio Fire Museum

The Amazing Mirror Maze

Children's Park

SEA LIFE San Antonio

Heads-up: tricky spots

Fuel & Cost

Travel Intel

Southmayd, TX

San Antonio, TX

Same local time

5 degrees warmer at arrival

6h 13m on the road

National Parks Near This Route

Waco Mammoth National Monument

San Antonio Missions National Historical Park

What kind of drive is this?

How Hard Is This Drive?

Elevation Profile

Towns Mentioned on Route Signs

About the Cities

Arriving in San Antonio, TX

Who Is This Route For?

Frequently Asked Questions

Which road carries most of the drive?

How do I pay the tolls on this route?

Are there rest areas on this route?

Should I avoid arriving after dark?

Is this a good trip with kids?

Where does this route get tricky?

Are there national parks near this route?

Can I do this as a round trip in one go?

How this page is built

Explore More

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