Hi there,
I just wanted to take the chance to contribute to this topic, as I am doing my DM in Iceland right now.
I dive Silfra nearly on a daily basis and I have done Gardur and Kleifarvatn in September 2014.
I am not sure wether you're allowed dive Silfra on your own, without a guide, but I'll find out tomorrow and let you know.
Although Silfra is a very easy site to dive, there are some things to consider:
* You should come with
drysuit experience, especially when diving alone. The depth profile is very much up-down-up-down, so the second you find good buoancy it is ruined again because you have to go up over a shallow part.
* If you dive here in winter, you need to have serious
cold water diving experience. I am not talking about < 20°C but <0°C. Although the water is constantly around 1-3°C, the air will
freeze your gear in seconds.
* There is only
one turn, that you can fail to take. If you do, you will end up in the nearby
lake and that could be a problem if you're on your own since the lake is frozen in winter and the current will pull you far in.
* The national park does not allow diving deeper than
18m and prohibits diving in
overhead compartments as well.
All the novice & experienced divers we take are happy to have a guide. The very experienced ones enjoy the fact that they are guided and thus have their head & hands free for their cameras.
I have written Blog articles about my dives in
Silfra,
Gardur and
Kleifarvatn (in German but with pictures & videos).
(Please remove the links if unwanted or let me know & I'll remove them!)
Please let me know if you have further questions and also if you're coming to Iceland as I am here for the next 2 months