Pacifica is an ocean planet, whose warm blue waters and fine white beaches make it a jewel in the galaxy. The USS Enterprise-D was en route to a scientific mission to Pacifica in 2364, when Captain Jean-Luc Picard diverted it to Dytallix B for a secret meeting. The stop at Pacifica was canceled due to ensuing events. (TNG: "Conspiracy")
In 2365, a conference was held on Pacifica concerning the admission of the Antedeans into the Federation. The Enterprise was assigned to transport two Antedean dignitaries to the planet, as well as Ambassador Lwaxana Troi. She would state that she wished to marry William Riker on the shores of Pacifica's Western Sea, though she was affected by the Betazoid phase at the time. (TNG: "Manhunt")
According to the Star Trek: Titan novels, Pacifica is part of the Federation and home to a spacefaring aquatic civilization known as the Selkies.