The boat that caught fire off California’s Santa Cruz island was on a three-day diving excursion that promised a stunning look at a rarely visited area.

The 75-foot vessel, called Conception, left from Santa Barbara Harbor on Saturday morning for the Labor Day weekend tour of San Miguel Island.

Worldwide Diving Adventures offered the trip as part of a $665 package that included “scrumptious” meals three times a day, snacks, non-alcoholic beverages, and unlimited air fills for divers.

“The beginning of September is the best time to be at San Mig, which see strong winds and swell during much of the year,” the company boasted on its website. “This rarely visited island is loaded with color: anemones, crabs, nudibranchs covering every inch of wall with a rainbow.”

Conception was set to return at 5 p.m. Monday. But a raging fire broke out on board around 3:15 a.m. while it was anchored near Santa Cruz island.

Thirty-nine people were on board, including five crew members who were rescued. The 34 passengers, who officials said likely were sleeping at the time, are unaccounted for and feared dead.