Saint Lucia is about 656 times smaller than California.

California is approximately 403,882 sq km, while Saint Lucia is approximately 616 sq km, making Saint Lucia 0.15% the size of California. Meanwhile, the population of California is ~37.3 million people (37.1 million fewer people live in Saint Lucia).
Tip: This to-scale comparison of California vs. Saint Lucia uses the Mercator projection, which distorts the size of regions near the poles.