The Pacific Ocean is used mostly for fishing and recreational boating. It attracts professionals from all around Panem in an annual tournament for a penthouse in District 1. District 17 and 14 both use the ocean as a food source and studying for scientific things.
Chiasa Izanami, heir to the Eastern District Throne, lives in the coast of the ocean in her home in District 17. On hot summer days, she'll scuba dive in the shallows of the ocean, and sometimes train her breathholding abilities as well.