There's a couple of drift dives on the north side. Most of the operators ride out there regularly. (town and all the resorts are on the south side)
Maybe the best dive on the south side is Black Hills. It's a pinnacle that rises to within about 40-50' of the surface. We saw more schools of large things (barracuda, oceanic triggers, grouper) on one dive there than anywhere else.
Review - Black Hills, Utila Island
There's about 3-4 wrecks off Utila, the Halliburton is the signature wreck -
Review - Halliburton Wreck, Utila Island We dove Ron's Wreck, I wouldn't do it again. It's just a small sailboat on it's side. Did find a few big grouper hiding in the coral nearby.
Labrynth is a good dive also. We dove it at night since it's just off the south side. Near our resort - several nights boats from town dove there.
On the north side, Duppy Waters was good, Pinnacles also but it's just about past rec depths if you do the swim thru - you come out around 122' IIRC. We saws several sharks there. Blackish Point is another good dive - often done as a 2nd dive since it's shallower.
Review - Blackish Point, Utila Island The West End is supposed to have several good drift dives, we only were out there once and it was too calm..
Depending on when in March, you might see Whale Sharks. So plan some (non-dive) excursions. I don't know how that works from town but from Deep Blue we went looking early afternoon after doing our 2-3 dives. There were several boats nearby from town every time anyone spotted one. The captains cooperate since they're each only allowed limited drops per sighting. It's snorkel only. If you're looking to buy a camera - the sharks we saw were typically in the 12-18' range - one closer to 30'. Something wide-angle might work better as you'll be fairly close - several of ours went right under the boat. We were there the very end of March/early April.