San Antonio is about 11 times bigger than San Francisco.

San Francisco (including the city proper only) is approximately 121 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 968% larger than San Francisco.
Tip: This to-scale comparison of San Francisco vs. San Antonio uses the Mercator projection, which distorts the size of regions near the poles.
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