It's great that you already know what career path you might like to try out. I recommend researching marine biology companies and institutions and getting a feel for the industry / space. Likely some of the large companies have formal internships that you can apply into on their career websites.
I also recommend talking to your biology professors and college career services about where you should intern during college for a marine biology internships. I'm sure they'll be able to give you more personalized help and can give you advice to steer you in the right direction.
Raymond recommends the following next steps:
I would recommend looking into the following organizations in California:
Aquarium of the Bay, San Francisco (near your current location)
Careers and Internships - https://www.aquariumofthebay.org/careers/
Volunteer Positions - https://www.aquariumofthebay.org/volunteers/
Near: California State University, Monterey Bay - https://csumb.edu/marinescience/
Monterey Bay Aquarium (I used to volunteer here)
Internships - https://www.montereybayaquarium.org/about-us/internships
Jobs - https://www.montereybayaquarium.org/about-us/job-opportunities
Volunteering - https://www.montereybayaquarium.org/join-give/become-a-volunteer
California Collaborative Fisheries Research Program (CCFRP) Internship at Moss Landing Marine Laboratories (MLML)
Best Marine Biology Programs - https://www.americanoceans.org/blog/best-marine-biology-program/