The Galápagos begins with transfer from the landing near the airport to a boat at dock or a dinghy to the boat; these can be tricky. Once on the boat, most islands are reached by dinghy (tricky accessing and disembarking from a boat) and landings - often "wet" landings involving getting out of a dinghy affected by waves and wading ashore.

On the islands the areas can be sandy beaches unsuitable for wheelchairs or broken, sharp lava.

Having been to Islas Galápagos more than once, I'd say it would be extremely challenging to anyone requiring a wheelchair for mobility.