London is about 1.2 times bigger than San Antonio.

San Antonio (map shows its 401 named neighbourhoods; the area covers the whole city) is approximately 1,292 sq km, while London (including the 32 boroughs of greater London) is approximately 1,572 sq km, making London 22% larger than San Antonio.
Tip: This to-scale comparison of San Antonio vs. London uses the Mercator projection, which distorts the size of regions near the poles.
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