It is 250.82 miles according to MapQuest.
Approximately 4 hours.
It's a little under a 4 hour drive.
250 miles taking this route:Take I-45 NORTH from Galveston to the SAM HOUSTON TOLLWAY - WEST at EXIT 32.Bypass HOUSTON via the SAM HOUSTON TOLLWAY; take the SAM HOUSTON TOLLWAY around to I-10 WEST to SAN ANTONIO. EXIT.Take I-10 WEST to SAN ANTONIO.
Google Maps estimates the driving time as 4 hours and 11 minutes.
It is 437.60 miles accoording to MapQuest.
It is 65.60 miles according to MapQuest.
It is 128.53 miles according to MapQuest.
Carlsbad, NM to San Antonio, TX is about 450 miles by road.
It is 114.25 miles according to MapQuest.
It is 173 miles according to Google Maps.
It is 451 miles according to Google Maps.
It is 279.02 miles accordiing to MapQuest.