It's an annoying thing that gnaws at the heart of
a diver who has to cancel a trip: not getting your
deposit back, even if you cancelled far in advance
of the start date. It hurts even worse when the dive
operator gets full fare from someone else who took
your vacated spot.
Subscriber Ralph Bishop (Ithaca, NY) wrote us to
  complain about Big Fish Expeditions, a dive trip outfitter
  based in British Columbia. He had booked a trip to
  Scotland to dive with basking sharks, but had to cancel
  due to unforeseen retirement. Even though Bishop canceled
  more than six months in advance, Big Fish did not return his $500 deposit. "This despite the fact that
  the trip is sold out already, and doubtless they will sell
  my place," he says.
Unfortunately, Ralph, I checked the Big Fish website
  and in its FAQ page, it says the deposit is nonrefundable
  and non-transferable. Truth is, I myself
  hate these kind of rules, but they are everywhere in the
  industry, and regardless of whether they resell your
  spot, the rules are clear. I think it's a black mark on the
  industry, but that's what we as travelers face. It stinks
  and we're stuck.
However, for the rest of you, Big Fish has one
  spot left on its July 12-18 Scotland trip to see basking
  sharks. Big Fish won't say whether that's Bishop's old
  spot, but it's now up for grabs. Try not to cancel.