Just one point of clarity ^ - the Sand Dollar "dock" is actually the property of Bonaire DIve & Adventure at Den Laman Condos and they've lately become pretty aggressive about discouraging it's use by Sand Dollar owners/guests. To the point that there's now a gate on that side. To compensate
Dive Friends/Sand Dollar constructed a tank house plus steps down to the beach for access to Bari Reef - one of the best shore dives. If I was going out on my own on a day stop, it would be high on my list. If you like diving the reef with the highest fishcount in the Caribbean..
We paid $5 once to dive at Habitat - use of the lockers/showers etc. was included. Bring a lock. From their dive dock you can dive the La Machaca wreck or swim north to the Cliff dive site. We did that then drifted back over the wreck - it's small and not worth a special dive.
None of the suggestions here or in the post above are walking distance though except Dive Friends at their Yellow Sub location in town. They also keep part of their fleet there so boat dives could be a possibility depending on your arrival/time in port. There's not a lot of
taxis on Bonaire either unless that increased with the cruise traffic.
Another I know nothing about is VIP Diving's
cruise program.
Bonaire diving is mostly clustered in a few mile radius of Town Pier so there's no worries about missing your sailing if it's later in the afternoon. Even Klein Bonaire - look off the left side of your ship in port, it's the flat island you see. Some of the
beach cruise excursions go there but there's no facilities for divers.
Oddly the Divi Flamingo - the dive resort within walking distance of Town Pier - actively discourages cruise ship walk-ins. Probably because it stresses their facility availability for their guests, lockers, boats etc. are limited there vs. Habitat or Buddy who have a lot of both.