Swaziland is about 354 times bigger than Bouvet Island.

Bouvet Island is approximately 49 sq km, while Swaziland is approximately 17,364 sq km, making Swaziland 35,337% larger than Bouvet Island.
Tip: This to-scale comparison of Bouvet Island vs. Swaziland uses the Mercator projection, which distorts the size of regions near the poles.