Dallas to San Antonio distance

Dallas to San Antonio by road

The fastest driving route is 273 miles (440 km) long and takes about 4 hr 55 min without stops or traffic. Almost all of it is on I-35: 271 mi of 273 mi.

The whole route stays in Texas. That’s an average of 56 mph (90 km/h). AAA recommends a break every two hours or 100 miles: with 2 stops of 20 minutes, the trip takes about 5 hr 35 min. The time is OSRM’s estimate with OpenStreetMap data: no traffic and speeds somewhat below the limits, so real trips can differ.

Straight-line distance and bearing

In a straight line, the shortest distance over the Earth’s surface, Dallas and San Antonio are 252 miles (406 km) apart. That’s the geodesic on the WGS84 ellipsoid, the distance “as the crow flies”.

The road is 8% longer: for every 100 miles in a straight line you drive 108. The route runs almost straight. Of the 40 US pairs in this series, it ranks 32nd for detour (the average is 14%).

From Dallas, San Antonio lies to the southwest (bearing 204°), and from San Antonio, Dallas lies to the northeast.

Halfway between Dallas and San Antonio

Halfway along the straight line, 126 miles (203 km) from each city, is the point 31.1066° N, 97.6650° W. It falls near Flat (Texas, pop. 354), 14.2 mi away.

By road, the halfway point is 137 miles (220 km) from each city, near Pendleton (Texas, pop. 649), 13.8 mi away. The two midpoints are 12.4 mi apart: if you want to meet halfway, the one on the road is the useful one.

Time zone and flight

Dallas and San Antonio share the same time all year: both are on Central Time.

No flight time is given: under 500 km (311 miles) in a straight line, time at the airport outweighs time in the air.

The two cities

Dallas sits at 428 ft (130 m) and San Antonio at 649 ft (198 m), 221 ft (67 m) higher.

Dallas has 1.3 million people and San Antonio 1.5 million people (Census Bureau estimate for 2025).