San Antonio is about 1.2 times smaller than Bangkok.

Bangkok is approximately 1,569 sq km, while San Antonio (map shows its 401 named neighbourhoods; the area covers the whole city) is approximately 1,292 sq km, making San Antonio 82.38% the size of Bangkok.
Tip: This to-scale comparison of Bangkok vs. San Antonio uses the Mercator projection, which distorts the size of regions near the poles.
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