Marine biologists must complete at least a bachelor’s degree, which takes about four years. Marine biologists who pursue master’s degrees may take an additional two to three years to complete their education, and earning a PhD will take up to six years more.ome colleges and universities offer undergraduate degree programs in marine biology. Marine biology students take courses that focus on oceanography, marine vegetation, marine invertebrates, marine vertebrates, and marine ecology. Many of the schools that offer marine biology programs are located near an ocean.