A common assumption about liveaboard diving is that it's a couples-and-groups activity, and a solo traveler will be the exception aboard. GSD's own experience running these expeditions says the opposite: roughly half or more of the divers on a given departure are traveling alone.
What tends to happen instead is that a boatload of strangers who share the same two interests — diving and marine conservation — spends a week or two together, and genuine friendships form. GSD has seen solo travelers who met on one expedition go on to book a second trip together afterward.
The appeal for a solo diver isn't only company, though. Time between dives on a liveaboard is real downtime — for reflection, for improving technique, for actually absorbing what the onboard scientist just explained — in a way a busier, more social group trip doesn't always allow. And the destinations themselves, Darwin, Wolf and the rest of the northern circuit, are remote enough that everyone is getting there the same way: by boat, solo or not.
Source: adapted from Galápagos Shark Diving's own published guidance on solo travel.