Phoenix is about 1.4 times bigger than Sao Tome and Principe.

Sao Tome and Principe is approximately 964 sq km, while Phoenix is approximately 1,342 sq km, making Phoenix 39% larger than Sao Tome and Principe.
Tip: This to-scale comparison of Sao Tome and Principe vs. Phoenix uses the Mercator projection, which distorts the size of regions near the poles.