South Georgia and South Sandwich Islands is about 5 times smaller than Slovenia.

Slovenia is approximately 20,273 sq km, while South Georgia and South Sandwich Islands is approximately 3,903 sq km, making South Georgia and South Sandwich Islands 19.25% the size of Slovenia.
Tip: This to-scale comparison of Slovenia 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. Slovenia