Ocean kayaking is a dramatically different sport than river kayaking, with different weather and water conditions to consider, as well as different scenery to explore. While most of the equipment for kayaking is fairly standard, such as a repair kit, a spare paddle, safety equipment, etc., there are several items that are unique to ocean kayaking that no well-prepared paddler should be without.
Standard kayaking equipment includes appropriate clothing, such as a wet suit, a bailing pump, a life jacket, a spare paddle and a repair kit. These are essential. Some freshwater kayakers opt not to use the spray skirt, but when kayaking in the ocean it should not be skipped.
Losing control on a river may mean you get wet or, at worst, have to abandon your boat. Losing control in the ocean is a much more dramatic situation. Accordingly, you should be prepared with emergency equipment for any contingency. Any outdoor sports dealer can sell you a small VHF radio, a flare and a strobe light, all of which are essential equipment for any seafarer.
The sea can be a much harsher environment than fresh water, so the list of recommended personal items is longer. Even when the sun is not bright, the magnification of light on the ocean can be harmful, so always have lip balm, sunscreen, sunglasses and a hat. Your personal equipment should also include waterproof stuff bags.
Even if you are sticking to the coast, pack a compass and a map of your area. Seal your map, folded to the local area, in a freezer bag so you can navigate without exposing it to the water.
If you plan to spend the day at sea, provide yourself with a gallon of drinking water. While trail staples such as energy bars, granola and jerky are all good to have, nothing hits the spot out on the sea like some warm soup served from a thermos.