Curacao is the “middle child” of the three Dutch Caribbean islands, between Bonaire and Aruba. The diving is very similar to Bonaire, although the reef has not had the prolonged protected status that much of it's sister island enjoys.
Getting to Curacao
Curacao's airport is served by several inter-island carriers as well as several North American airlines. If you're coming from the west coast of the states you may wish to consider flying via Panama on Copa airlines. Note that inter-island flights are notoriously spotty, so it pays to keep an eye on your flight status.
Curacao Dive Resorts
There are a number of dive resorts along the south-west coast of the island. Many have their own dive operations. The only one I have direct experience of is the Oasis Coral Estate Beach, Dive & Wellness Resort, formerly known as the Habitat Curacao Dive Resort. The resort was completely reconstructed after being taken over by the Coral Estate. See below for more hotel options.
While you can short dive around Curacao, and some of the dive sites are quite close to shore, the island isn't as well set up for independent divers as much as its neighbor Bonaire. Sites are not clearly marked and there aren't many operators catering to those that just want to get tanks filled. If you really want to just shore dive, you might want to check out The Dive Bus, which seems to specialize in shore diving.
Other dive operators seem to do mostly boat dives. Depending on current, you may end up drift diving, but most of the time the boat will drop you in and pick you up in the same spot. In most places there's a sandy bottom dotted with coral heads, out to a reef wall that may be at a depth of 40 to 60 feet.
Deco Day Activities
You have a few choices for activities on your no-dive day. A very common option is to spend an afternoon in the old part of Willemstad. There are a couple of casinos, if you're so inclined, but most prefer to poke around the old town area, with its colorful buildings, relaxed cafes, and other shops as well as museums. The floating pedestrian bridge which crosses the mouth of the harbor is a sight in itself. If you spend enough time in the area you'll get to see it swing open for a passing ship.
Another option I quite enjoyed as I was staying at the Oasis Coral Estate was a hike from the resort up around Saliña Sint Marie. The desert landscape is quite interesting, and there's a chance you might see some flamingos, although they tend to congregate at the north end of bay, which is a long hike.