South Georgia and South Sandwich Islands is about 64 times bigger than San Marino.

San Marino is approximately 61 sq km, while South Georgia and South Sandwich Islands is approximately 3,903 sq km, making South Georgia and South Sandwich Islands 6,298% larger than San Marino.
Tip: This to-scale comparison of San Marino 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. San Marino