San Diego is about 2.2 times bigger than Saint Vincent and the Grenadines.

Saint Vincent and the Grenadines is approximately 389 sq km, while San Diego is approximately 844 sq km, making San Diego 117% larger than Saint Vincent and the Grenadines.
Tip: This to-scale comparison of Saint Vincent and the Grenadines vs. San Diego uses the Mercator projection, which distorts the size of regions near the poles.