A foam board is, well, it’s a board made out of foam, kind of like a large boogie board. It is bigger and more buoyant than a fiberglass board, and because of its rough surface, it doesn’t need to be waxed. Also, foam boards won’t seriously hurt if they crash into you (which they undoubtedly will). A fiberglass board is a foam (a different kind of foam) blank that is hand-shaped and covered with a hard fiberglass layer that makes it light and durable, and able to glide easily on water so that you can perform maneuvers and tricks. The drawback of a fiberglass board is that it can be easily damaged with cracks or dings that need to be repaired.
The newest of newbies should consider taking a lesson or two on a large foam board before making any purchases. It’s a good idea to rent a foam board for your first couple of forays out on your own. If you think you may only be a fair-weather surfer who never gets much beyond the white water or if you have trouble with your knees or are (ahem) an older Betty, a Soft-Top may be the ideal board for you. These have foam decks but fiberglass bottoms so they ride better but aren’t as hard on your body. If you have been bitten by the surf bug and plan to be out in the ocean often, a fiberglass board would probably be best for you.
Enjoy the ride,