San Antonio is about 1.2 times smaller than London.

London (including the 32 boroughs of greater London) is approximately 1,572 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 82.21% the size of London.
Tip: This to-scale comparison of London vs. San Antonio uses the Mercator projection, which distorts the size of regions near the poles.
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