Biloxi sits in the middle of a coast that runs in a straight line, which makes it an unusually good base. Interstate 10 runs east and west a few miles inland, US 90 runs along the water the whole way, and almost everything worth a day is strung between them. Nothing here requires a ferry booking or a mountain pass. The skill is in choosing, because the coast rewards short trips far more than long ones.
Most visitors get this backwards. They arrive, see that New Orleans is ninety-odd miles west, and spend a day of a four-day holiday driving to a city that deserves three days of its own, while ignoring an arts town ten minutes east across a bridge. New Orleans is a fine day out and there is now a train that makes it a better one. It is still not the best use of your first free day here.
The near trips are the strong ones. Ocean Springs is ten minutes over the Biloxi Bay Bridge and is the most walkable old downtown on the Mississippi coast, with the Walter Anderson Museum of Art in the middle of it. Gulfport is twenty minutes west and has the aquarium, the children's museum and the harbour the Ship Island ferry sails from. Bay St Louis is forty-five minutes west and is the coast's prettiest small town. And at Gautier, twenty-five minutes east, a national wildlife refuge protects an endangered crane found nowhere else on earth, on a wet pine savanna almost nobody stops for.
One structural warning about planning. Ship Island is not a day trip in the sense used on this page; it is a whole day that starts at a Gulfport dock and ends when the boat comes back, and it has its own page for good reason. Do not try to combine it with anything else. Similarly, a day in New Orleans that also takes in the coast's towns is two days pretending to be one.
Below: the drive times, what each town is genuinely for, which trips work for children, and how to reach New Orleans without a car now that scheduled trains have returned to this line.