The Keys are mostly boat dives. With 4 divers that can get expensive fast.
None of these are cheap places to stay either but the diving could be more reasonable from shore. A quick Google Flights check indicates all are 12-15 hours, one stop and less than $1200 for flights - some as cheap as $700. I used a week in March, Sat-Sat.
Grand Cayman is no doubt pricey. But renting a condo, doing some cooking cuts into that - although food in the stores is high also. For your new divers - there's a 1/2 dozen decent shore dives. North to South highlights:
Cobalt Coast Resort - Reef Divers on-site now for tanks or boat dives. So shallow they used to tow experienced divers out to the wall.
Turtle Reef - a mini-wall that doesn't exceed 40-50' to the south, slightly deeper north. Sundivers on site with easy stairs entry. Also Macabuca for lunch.
Lighthouse Point - another shallow dive - the anchor/historical site is 15'? Divetech on site.
Cemetery Beach - almost a better snorkel. No operator
In Georgetown Eden Rock isn't much deeper than 40' anywhere - some of the reef closer to 15'. Devils Grotto just to the south is similar.
South of town is Sunset House - the dive resort. Two shore dives there - the mermaid might be too deep for the kids (55') but hey might like waving at the tourist sub when it goes by. Also there's a shallow reef just off saltwater pool entrance - couldn't have been 20' deep.
Slightly farther south is Smith's Cove - it's shallow for a while. Get tanks for both Smiths and Cemetery at Eden Rock or Divers Supply slightly north of town. Know that Georgetown is a big cruise port and the tenders dock downtown.
Plus there's two boat dives they can do - the Kittiwake - a dive cleaned wreck deliberately put down. So shallow recent rough waves just tore the roof off the Pilothouse. Check on penetration though since they're
junior OWD. DM accompanied and they cut big holes in the hull.
Dive 365
The other dive is Stingray CIty - the best 14' dive in the world. You're encouraged to overweight to plant yourself in the sand while feeding the rays.
A lot of the 2nd dives from a boat on the morning 2-tank are shallow but most still about 40' or so. Red Sail Watersports does one in the afternoons that's also a snorkel trip so they stay to shallower sites. The problem with the deep dives is that due to the moorings, someone wanting to stay shallow is in blue water with nothing nearby.
Curacao is an option also. About 40 beach entry dive sites with facilities on-site. The 4-5 that need a dive dock have one. Really easy, low current diving - at many no current at all. One of their signature dives is the Tugboat - it's 17' deep. The pier nearby 40' but the good stuff starts at 10' At Playa Jeremi there's a field of Orange Cup Corals in 15' off the north point of the protected cove. Several other sites are similar. A couple of the resorts with diving also have a breakwater so the water between it and the beach is pretty calm.
Scuba Shore Diving Site Listing for: Curacao, ABC Islands
Last option - the Virgin Islands. Flights go into St. Thomas - take the
Fast Ferries to the British Virgin Islands - lots of expat Brits there. Pretty expensive - Virgin Gorda is really quiet. Tortola a little busier. DiveBVI lists depths - some as shallow as 20-30'. All
boat dives.
BVI Scuba Diving Sites | Dive BVI
If you split your time, spend a few days on St. Thomas's East End. Coki Beach is a shallow beach dive - IDK if it exceeded 40' anywhere. The signature boat dive in the area, Cow/Calf rocks about the same. We did a shallow drift dive off Grass Cay - I'm positive it wasn't much deeper than 30'. That whole area is pretty shallow. Also you can "drive" (car ferry) over to St. John - there's a couple shallow dives there also - plus several snorkel trails.
