Honestly there are very few good beaches on Bonaire. Within walking distance of a condo - narrows it down to about 1. And it's a tiny beach
at Sand Dollar condos - most of it is ironshore above the water except for the small strip you can see in some photo. Bari Reef is the dvesite just off the beach.
The other places that have beaches are the villas at Harbour Village which is the most expensive property there or the villas/condos at the Plaza Resort but they're on the south end and the beach is a decent walk to the NW side and it's a pretty sprawling resort.
There;s kind of a beach at Lighthouse Point condos but the condos themselves are set back from it a good distance and the few on the beach are private - not rented. It's also near nothing in south Belnem so you'd be driving them everywhere. Next to Den Laman condos - which is next to Sand Dollar is Coco Beach Club - a day use beach spot.The beach there in some areas is kept onshore by a curb.
Honestly there's about 5 things other than diving to do on Bonaire and all require a car. The donkey farm. the lighthouse,watch the kitesurfers at Lac Bay - which btw is on the east side south - not near most of the dive sites/condo properties, possibly tour up into Slagbaai Park and Rincon one day - maybe see the flamingos at Gotomeer on the way. Road signs are metric in case they're from a country that is also. And there's no public transportation outside of a few cabs. Some of which will be busy when a cruise ship docks at Town Pier.
You should really look at Curacao instead. Possibly Lions Dive resort as it has a beach and is in an area with nearby shops - a small mall, the Aquarium - all within walking distance.They also have a shuttle to Willemstad which is a couple miles away and there's a lot of historical stuff there - a museum, some forts, the oldest synagogue in the western hemisphere, a lot of shopping in the old downtown - there's even a trolley that tours most of it. If you can work out the language issues - Curacao has a bus system. We saw one a couple times in more remote places.
Another option would be condos in Piscadera Bay - the public beach is just down the hill. You can also get them a day pass to the Hilton or there's a small beach at Pirates Bay - a beach bar. A few minutes drive away is Blue Bay beach - you could dive the wall there while they stay on the beach.
There's actually quite a few options like that - Varseenbaai is a local beach plus a good dive site. There's a restaurant on site there as well as Trunk Divers. If they snorkel, there's turtles just off the beach in 6' of water. Porto Mari is both a locals beach and a good double reef dive. Cas Abao is both. Playa Lagun is both with a cliffside bar/grille. Playa Jeermi is a nice beach but no facilities there. All that I've named have a dive operation, some sort of food, bathrooms, shade etc. something you won't find anywhere on Bonare. And there's at least 1/2 dozen more similar sites - the 2 Gnip sites, Playa Kalki etc.
Curacao is the same diving as Bonaire - maybe better in some areas. Certainly the shore dive entries are much easier - off the beach instead of over the ironshore. Curacao has more verticality at the northern sites than anything you see on Bonaire.1/2dozen sites have some sort of sloping wall.
And once you leave town there are no facilities at any dive site on Bonaire - none. Except where the kitesurfer food truck is that morning. Even at a site like Pink Beach - there's no shade, no food/water - nothing. And beach is being optimistic - there's still ironshore in the water there.It will shred your feet without boots or at least rubber soled surfwalkers.
