The truly amazing thing about sea kayaking excursions is you get to see areas of the shoreline which are usually inaccessible. Nonetheless, what kayaking craft you use will depend on where you are really taking your trip.
The types of kayaks that they use for warm waters are different from those, which are used where it's chilly. If you are planning to get married and have an adventurous honeymoon which includes activities like kayaking, diving, etc., you may have a look at http://www.paradiseinfiji.com/wedding/.
Even though you will end up with a great tan on your own legs at the end of the excursion, it also makes it far easier for you if and when the kayak tips over. What you need to do is flip the craft back over and then climb back on to it.
However, if your trip is definitely going to be in areas like Canada or Alaska subsequently safety is a major issue. For all these excursions, your kayak will have a cockpit in which you sit and which a spray skirt covers over to prevent water actually getting access into the hull of the kayak.
In order to propel the kayak along, you should have upper strength in both shoulders and your arms and need to be reasonably fit. Do not forget it is these which will be pushing against the paddles through the water also and to help propel the kayak forward to assist you to slow down and halt.