Tanjung Benoa
The heart of it — a kilometre of operators. Thirty to sixty minutes of reef viewing, usually bundled with Turtle Island. Sheltered and calm most of the year.

Charters by day shape
The easiest way for non-swimmers, small children and grandparents to see live coral — and an honest account of what the panel actually shows.
Set expectations correctly and the trip delights; oversell it and it disappoints.
Where they run
Short trips, cheap to operate, running continuously through the morning. There is no advance-booking culture, though a hotel or driver will pre-arrange one happily.
The heart of it — a kilometre of operators. Thirty to sixty minutes of reef viewing, usually bundled with Turtle Island. Sheltered and calm most of the year.
Reef-flat viewing inside the lagoon. Calmer than the Benoa strip, and the better version of "see the reef without swimming".
Same reef, whole boat, a snorkel guide and your own hours. This is where the desk actually helps.
A glass bottom boat needs no desk — walk onto the beach. If you want the same reef on your own hull with a snorkel guide and your own hours, that is what the desk is for.