You must be a certified diver or, at least, an avid snorkeler. There really aren’t any quiet beaches for working on your tan.
You should be a relatively experienced diver. Tubbataha is famous for ripping currents and deep dives. You should also be in relatively good shape, because multiple dives over multiple days demand stamina. [Related story: Their love affair with Tubbataha]
You should book in advance. Some foreigners book a year before, because the Tubbataha dive season is short—only March to June of every year.
You should research on the costs and facilities of the live-aboard boats that go to Tubbataha. Most of them are run by reputable operators, but do ask around, read testimonials, ask people who have been on the boats. Among the popular vessels are Discovery Palawan, Palausport, Oceana Maria and Azores (they’re all online).
You should make arrangements to fly in and out of Puerto Princesa, which is not included in the cost of the trip. Give yourself time on the return trip; your flight should be 24 hours after your last dive.
You should save money. A trip to Tubbataha is not cheap—around $2,000 per person. But if you’re a serious scuba diver, it’s worth it.