How far is San Antonio, TX from San Marcos, TX?
The driving distance from San Antonio, TX to San Marcos, TX is about 49.5 miles (79.6 km), with a travel time of about 00h 58m by car.
- The straight-line flight distance is about 45.9 miles (73.9 km).
- For a round trip, plan for roughly 01h 57m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 8:00 AM to 10:00 AM CDT.
Reverse, save, or send this route
This route works well as a day trip with time at the destination. Copy the route link, send it to another device, or print a clean version before you head out.
This route works well as a day trip with time at the destination.
Flight Distance
Driving Distance
Gas Cost Calculator
Leave and Arrive Planner
Pick a departure time to see your estimated arrival and same-day return window.
Drive time stays fixed at 00h 58m.
A morning start gives you useful time at the destination and keeps the return out of the late evening.
You are leaving earlier than the recommended window, which gives you extra margin for breaks and traffic.
Halfway Point
A useful midpoint for breaks, coffee, or meeting in the middle.
City in Guadalupe County, Texas, United States
Route Weather Snapshot
Check the forecast at both ends before you head out.
Partly Sunny
Sunny
Driving Route Map
The map below follows the saved road route between San Antonio and San Marcos.
Turn-by-Turn Driving Directions
Step-by-step road directions between San Antonio and San Marcos.
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1
Start on Dolorosa Street
44 m · 5 sec · Dolorosa Street
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2
Continue on West Market Street
1893 ft · 42 sec · West Market Street
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3
Continue on East Market Street
2143 ft · 46 sec · East Market Street
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4
Turn left
111 m · 13 sec
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5
Turn straight onto East Commerce Street
66 m · 13 sec · East Commerce Street
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6
Take the ramp sharp left toward US 281 North, I 37 North
1159 ft · 28 sec
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7
Merge slight left onto William J Bordelon Freeway
1.3 km · 56 sec · William J Bordelon Freeway
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8
Take the exit slight right toward I 35 North: Austin
2907 ft · 1 min
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9
Merge slight left onto North Pan Am Expressway
8.2 mi · 10 min · North Pan Am Expressway
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10
Keep slight left to continue on North Pan Am Expressway
7.4 mi · 8 min · North Pan Am Expressway
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11
Continue on Purple Heart Trail
11.9 mi · 13 min · Purple Heart Trail
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12
Continue on Interstate Highway 35
1.9 mi · 2 min · Interstate Highway 35
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13
Continue on Purple Heart Trail
15.9 mi · 17 min · Purple Heart Trail
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14
Take the exit slight right toward Loop 82 West, TX 123 South: Seguin
1008 ft · 25 sec
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15
Turn straight onto South Interstate 35
1058 ft · 23 sec · South Interstate 35
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16
Turn left onto South Guadalupe Street
2523 ft · 52 sec · South Guadalupe Street
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17
Turn right onto East Grove Street
120 m · 8 sec · East Grove Street
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18
Turn left onto South LBJ Drive
2988 ft · 1 min · South LBJ Drive
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19
Turn left
128 m · 36 sec
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20
At the end of the road, turn left onto North Guadalupe Street
43 m · 3 sec · North Guadalupe Street
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21
Arrive at your destination
0 m · 1 sec · North Guadalupe Street
Car Route Details
A richer read on the saved driving route between San Antonio and San Marcos.
Turn-heavy local drive
The route has frequent decision points for its length, so lane choice and turn timing will matter more than cruising speed.
Purple Heart Trail
Continue on Purple Heart Trail
15.9 mi · 00h 17m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A comfortable day-trip route
This route works well as a day trip. You can leave in the morning, spend meaningful time at the destination, and still return the same day.
Partly Sunny leaving San Antonio and Sunny near San Marcos.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from San Antonio to San Marcos?
The road trip is about 49.5 miles (79.6 km) and usually takes 00h 58m in normal driving conditions.
Is this a same-day trip or an overnight route?
This route works well as a day trip. You can leave in the morning, spend meaningful time at the destination, and still return the same day.
What is the halfway point on this route?
Cibolo is a useful midpoint, sitting about 24.7 miles from San Antonio and 24.7 miles from San Marcos.
How much longer is the road route than the straight-line distance?
The direct path is about 45.9 miles (73.9 km), while the road route adds roughly 3.6 extra miles because roads do not follow the straight air line.
When is the best time to leave for this route?
A good departure window is usually 8:00 AM to 10:00 AM CDT. If you want a more comfortable same-day return, try to leave by 4:32 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $6.61 one way or $13.23 round trip. Estimated CO2 is about 15.6 kg one way.
What should you check before leaving?
Before you leave, expect Partly Sunny around San Antonio and Sunny near San Marcos.
Stop Ideas Near Cibolo
Useful break, food, and waypoint ideas within about 15 miles of the route midpoint.
New Braunfels Parks and Recreation
Schertz EMS
Windcrest City Hall
Comal County Courthouse(Gerichtsgebäude)
Transit and Meeting Points
Useful pickup, handoff, or rendezvous points close to Cibolo.
San Antonio Station
San Marcos Station
Austin
Flight Path Map
This map shows the direct air route between San Antonio and San Marcos. Straight-line distance: 45.89 mi (73.85 km).
#1 San Antonio
The seventh most populous city in the United States and the center of the San Antonio metropolitan area.
| Population | 1,567,118 |
| Coordinates | 29.4241200, -98.4936300 |
| Altitude | 198 |
| Country | United States |
#2 San Marcos
The most populous city in Hays County, Texas.
| Population | 66,350 |
| Coordinates | 29.8832700, -97.9413900 |
| Altitude | 188 |
| Country | United States |
End: San Marcos (-97.94139, 29.88327)
Estimated Travel Time
Distance: 80 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 01h 38m |
| 40 mph (64.37 km/h) | 01h 14m |
| 50 mph (80.47 km/h) | 00h 59m |
| 60 mph (96.56 km/h) | 00h 49m |
| 70 mph (112.65 km/h) | 00h 42m |
| 80 mph (129 km/h) | 00h 37m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.78 | $6.61 | $13.23 |
| Mid-grade | $4.25 | $7.44 | $14.88 |
| Premium | $4.59 | $8.03 | $16.07 |
| Diesel | $3.99 | $6.99 | $13.98 |
Assumes 8.3 L/100 km (about 28.3 MPG). CO2 is an estimate and varies by vehicle, fuel blend, traffic, and terrain.
Prices in Texas · Jun 02, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.