St. Petersburg, FL to North Key Largo, FL is 298 miles and takes about 5h 39m via I 75 and Homestead Extension of Florida's Turnpike, with a fuel budget near $51 and enough daylight to finish in a day. This trip stays within Florida, taking you from the Gulf Coast across the state and down into the Keys. With a high percentage of highway driving, expect a relatively straightforward trip. It's a solid option for a single-day drive, though you could easily extend it if you prefer a more relaxed pace.
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
149 miles from St. Petersburg, FL
A natural place for your longest stop of the day
, about 2h 44m into the drive
.
Main Roads
Road
Distance
Duration
I 75
203.8 mi
3h 38m
Homestead Extension of Florida's Turnpike
34.5 mi
40m
US 27
17.9 mi
22m
Card Sound Road
16.5 mi
23m
Sunshine Skyway Bridge
13.4 mi
15m
I 275
6 mi
8m
CR 905
1.7 mi
2m
Dixie Highway
1 mi
1m
Longest stretch:
I 75
— 203.8 mi, about 3h 38m
Traffic on I-75
Hour-of-day weekday pattern from 92 FHWA count stations on your route.
Peak
4 PM
~2,826 veh/hr typical
· worst 3,424
Quietest
2 AM
~185 veh/hr
Peak-to-quiet ratio
15.3×
busier at peak than in the quiet hours
12a6anoon6p11p
Averaged across 52 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 St. Petersburg, FL and North Key Largo, FL.
1
Start on US 19
48 ft·5 sec·34th Street South
2
Turn right onto CR 150
0.2 mi·50 sec·Central Avenue
3
Turn right onto 31st Street South
0.7 mi·1 min·31st Street South
4
Take the ramp
0.5 mi·1 min
5
Merge onto I 275
4.9 mi·5 min·I 275
Use the straight / slight right lanes.
6
Keep slight left at fork
0.3 mi·17 sec
7
Merge onto I 275; US 19
13 mi·15 min·Sunshine Skyway Bridge
Use the straight / slight right lanes.
8
Keep slight left at fork onto I 275
1.1 mi·2 min·I 275
Toward I 75 South: Naples
9
Merge onto I 75
28 mi·30 min·I 75
Use the straight / slight right lanes.
10
Keep slight left at fork onto I 75
176 mi·3 hr 8 min·I 75
Use the straight / slight right lanes.
11
Take the exit
0.2 mi·21 sec
Toward US 27: Miami, South Bay
12
Keep slight right at fork
0.5 mi·58 sec
Toward US 27 South: Miami
13
Merge onto US 27
9.2 mi·11 min·US 27
Use the right lane.
14
Keep slight right at fork onto US 27
8.6 mi·11 min·US 27
Use the straight lane.
15
Take the exit
0.3 mi·32 sec
Toward Florida's Turnpike South: Homestead, Key West
16
Merge onto Homestead Extension of Florida's Turnpike
35 mi·40 min·Homestead Extension of Florida's Turnpike
Use the straight / slight right lanes.
17
Keep slight left at fork
0.6 mi·1 min
18
Merge onto US 1
1.0 mi·1 min·Dixie Highway
Use the left lane.
19
Turn left onto Card Sound Road
17 mi·23 min·Card Sound Road
Use the left lane.
20
Turn right onto CR 905
1.7 mi·2 min·CR 905
21
Arrive at destination
CR 905
Trip Plan
For this 298-mile drive, leaving St. Petersburg in the morning allows you to reach North Key Largo before evening. The total driving time is under six hours, so one stop should be sufficient. Keep an eye on your fuel gauge, especially during the longer highway stretches, and utilize the numerous service areas along I 75 and the Turnpike. Since it's manageable in a single day, you have the flexibility to depart when you feel most rested.
Morning Departure
An early start around 7-8 AM gets you there with plenty of daylight left.
Evening Departure
A late afternoon start means arriving after dark. Morning is better.
You can normally do this drive in one day.
Plan roughly 1 meaningful break for fuel, food, and rest.
The halfway point lands around 149 miles from St. Petersburg, FL, or about 2h 44m into the drive.
The longest continuous stretch on this route runs about 203.8 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 66 miles or 1h 15m in
Use this first pause for coffee, a restroom break, and a quick traffic check ahead.
Halfway reset
Around 149 miles or 2h 44m in
This is the best place for your longest stop, a real meal, and a full fuel check.
Final approach
Final hour starts around 4h 30m
Traffic, exits, and arrival timing usually matter more near North Key Largo, FL than in the middle of the route.
Before You Leave
+
Open the route before leaving St. Petersburg, FL 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 St. Petersburg, FL
This is one driving day of about 298 miles and 5h 39m.
Your first comfortable stop window is around 66 miles from St. Petersburg, FL.
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 I 75 for about 203.8 miles.
Where to Stop
Rest stops, refuel points, and overnight suggestions along this route.
Place data sourced from public business listings. Hours and availability may vary.
Heads-up: tricky spots
5 of 18
5 decision points cluster between mile 0 and 279.8 — GPS handles the exact turns, but know they're coming. Your lane choice matters more than the turn itself.
5
0 mi into trip|~0m in|CR 150 / Central Avenue
Turn right onto CR 150 / Central Avenue
Navigation decision point
5
1.5 mi into trip|~3m in|I 275
Merge onto I 275
Merge point - match speed before joining. Lane positioning matters here
Use the straight / slight right lanes.
6
49.2 mi into trip|~57m in|I 75
Keep slight left at fork onto I 75
Highway fork - watch signs carefully. Lane positioning matters here
Use the straight / slight right lanes.
6
234.8 mi into trip|~4h 18m in|US 27
Keep slight right at fork onto US 27
Highway fork - watch signs carefully. Lane positioning matters here
Use the straight lane.
6
279.8 mi into trip|~5h 13m in|Card Sound Road
Turn left onto Card Sound Road
Lane positioning matters here
Use the left lane.
Fuel & Cost
Regular Gas
$45.11 one way
$90.22 round trip
$3.85/gal25.4 MPG avg104 kg CO2
Fuel Type
$/gal
One Way
Round Trip
midgrade
$4.22
$49.50
$99.00
premium
$4.55
$53.38
$106.76
diesel
$4.80
$56.27
$112.54
Estimated Tolls: $3.01
Homestead Extension
(34.5 mi)$2.07
Sunshine Skyway Bridge
(13.4 mi)$0.94
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
$45
Tolls
$3
Meals
$25–$50
Total
$73–$98
Rough estimate based on US averages. Hotel $80–$140/night, meals $25–$50/day.
Estimated CO2 emission: 104.3 kg one way.
Prices: EIA weekly data, 2026-07-13.
Driving Electric?
About $31 in charging
· 1 stop
· 66% less CO2
Vehicle Type
kWh
Stops
DC Fast
Home Charge
Average EV
89.4
1
$31.29
$14.30
Efficient EV
74.5
0
$26.08
$11.92
EV Truck/SUV
119.2
1
$41.72
$19.07
Gas CO2
104 kg
EV CO2
35 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 Jul 17, 2026
Origin
St. Petersburg, FL
Late night
in St. Petersburg on Monday
Local time
3:19 AM
EDT
Current temp
91°F
Scattered Showers And Thunderstorms
NW 7 mph54% chanceLive forecast
Severe Thunderstorm Warning
Severe Thunderstorm Warning issued July 17 at 5:24PM EDT until July 17 at 6:00PM EDT by NWS Jacksonville FL
Special Weather Statement
Special Weather Statement issued July 17 at 5:18PM EDT by NWS Tampa Bay Ruskin FL
Destination
North Key Largo, FL
Late night
in North Key Largo on Monday
Local time
3:19 AM
EDT
Current temp
92°F
Slight Chance Showers And Thunderstorms
S 5 mph18% chanceLive forecast
Severe Thunderstorm Warning
Severe Thunderstorm Warning issued July 17 at 5:24PM EDT until July 17 at 6:00PM EDT by NWS Jacksonville FL
Special Weather Statement
Special Weather Statement issued July 17 at 5:18PM EDT by NWS Tampa Bay Ruskin FL
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
1 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
5h 39m on the road
An early start around 7-8 AM gets you there with plenty of daylight left.
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.
De Soto National Memorial
National Memorial
In May 1539, Conquistador Hernando de Soto’s army of soldiers, hired mercenaries, craftsmen, and clergy made landfall in Tampa Bay. They were met with fierce resistance of indigenous people protecting...
8 mi from route
~19 min detour
Free
near mile 10.3
Within sight of Miami, yet worlds away, Biscayne protects a rare combination of aquamarine waters, emerald islands, and fish-bejeweled coral reefs. Evidence of 10,000 years of human history is here to...
11 mi from route
~27 min detour
Free
near mile 267.2
Established in 1947 as the first national park created for its biodiversity, Everglades National Park protects 1.5 million acres of wetland, forest, and marine habitats and the native plants and anima...
27 mi from route
~67 min detour
$35
near mile 277.5
Park data from the National Park Service API. Alerts update every 2 hours.
More Details
What kind of drive is this?
This drive is primarily highway, with 89% of the route on major roads. You'll have a long stretch of 203.8 miles on I 75 before transitioning. The Homestead Extension of Florida's Turnpike will then carry you for a significant portion. Expect frequent exits and changes in traffic patterns as you get closer to South Florida.
89% highway — fuel and pacing are the main things to plan.
21 navigation steps total — most of the decisions cluster near the start and finish.
Longest single stretch: 203.8 mi on I 75.
How Hard Is This Drive?
9/10
This is a straightforward highway drive that stays mostly on I 75 and Homestead Extension of Florida's Turnpike. This route has several spots where lane changes, forks, or exits need your full attention. The trickiest moment comes early in the drive near CR 150 / Central Avenue.
Driving Effort9/10
High effort - long or complex enough to need steady focus all day
Balances navigation complexity with total wheel time.
This is a demanding drive. With 18 significant decision points across 298 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: near the start (CR 150 / Central Avenue): Navigation decision point; at 1.5 miles (I 275): Merge point - match speed before joining. Lane positioning matters here; at 49.2 miles (I 75): Highway fork - watch signs carefully. Lane positioning matters here.
Elevation Profile
Mostly flat terrain
43 ft6 ft
Total Climb
31 ft
Total Descent
68 ft
Highest Point
43 ft
Elevation Range
37 ft
Towns Mentioned on Route Signs
Based on OSRM destination-sign hints, not a full list of every settlement the road passes.
Between St. Petersburg, FL and North Key Largo, FL, road signs point toward Bay, Florida's Turnpike South: Homestead and Key West.
Saint Petersburg sits at the base of the Tampa Bay peninsula in Pinellas County, Florida, and enjoys a more subdued social atmosphere than its larger cousin, Tampa. The city has tried to characterize the downtown as an arts and entertainments destination and you will find no shortage of arts and crafts stores, galleries, and museums along with cafes and boutique food shops all within a couple blocks of the Tampa Bay waterfront. With water on three sides of the city, St. Pete is a superb location for fishing, sailing, and wandering beaches.
Top landmarks
•Salvador Dalí Museum — art museum in St. Petersburg, Florida, United States
•Vinoy Park Hotel — historic hotel in St. Petersburg, Florida, USA
•Museum of Fine Arts, St. Petersburg, Florida, USA — museum in St. Petersburg, Florida
Doable as a same-day drive at 5h 39m. Total distance: 298 miles.
Family Friendly
Moderate complexity with 1 natural rest stops along the way.
Solo Traveler
5h 39m drive, comfortable solo distance.
First-Time Driver
Mostly highway driving (89%). Some complex stretches to watch for.
Frequently Asked Questions
The longest stretch is about 203.8 miles on I 75. The full list of main roads is in the Roads section above.
Expect about $3.01 in tolls one way, starting with Homestead Extension. 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 16 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 North Key Largo, FL 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 16 rest areas along the route for bathroom stops.
The main spots that need attention: near the start (CR 150 / Central Avenue): Navigation decision point; at 1.5 miles (I 275): Merge point - match speed before joining. Lane positioning matters here; at 49.2 miles (I 75): Highway fork - watch signs carefully. Lane positioning matters here.
Yes — De Soto National Memorial, Biscayne National Park and Everglades National Park. See the National Parks section for detour distances and tips on detours.
Not recommended in a single day. At 5.7 hours each way, a round trip means 11.3 hours of driving — that is an unsafe level of fatigue for most drivers. Plan at least one night at North Key Largo, FL before the return drive.
