South Georgia and South Sandwich Islands is about 503 times smaller than Mexico.

Mexico is approximately 1,964,375 sq km, while South Georgia and South Sandwich Islands is approximately 3,903 sq km, making South Georgia and South Sandwich Islands 0.2% the size of Mexico.
Tip: This to-scale comparison of Mexico vs. South Georgia and South Sandwich Islands uses the Mercator projection, which distorts the size of regions near the poles.
Compare further: South Georgia and South Sandwich Islands vs. Mexico