My Wife and I did our SSI Open Water Diving Qualification last year on Koh Phi Phi.
Many people would say do PADI and not SSI, but both are as good as each other and both are recognized all around the world.
I recommend doing the course when on holiday, much more relaxed and you get to see some very cool sea life.
It cost us 350 Euros each, This included the full kit hire, 4 days of diving and the Certification.
There was an exam of which you needed to get 85% to pass.
The Diving was two sessions per day of 30m each (or until you ran out of air)
We progressed from shallow water to deep water during the course.
During the dives you will be expected to carry out some skills, such as sharing Air with your buddy, removing your mask and then refitting whilst 10+meters down and various other skills that are required to be certified.
My wife managed it all very well, the main issue she had was to maintain the correct buoyancy, she was looking at fish so much she kept drifting up, which lead to me having to then pull her back down. I got the hang of being able to control my weight in such a way i could gently tug her downwards and stay where i was.
It was a very fun experience, we have booked a holiday to lanzarote this august and we plan to take our qualification and go diving there.
Its a serious thing though, you have to look after each other and check your air levels and depth. Also you will need to keep checking your buddies levels as they wont be the same as yours.
You have to keep calm and collected and respect the environment you are in.
When you are say 20M down, you cant simply decide to go up the surface, you have to surface gradually and also take a break at around 10m and then 5m. How long the stop depends on your dive computer.
Also just for reference:
These are the recommended depths by certification by the SSI standards. They are recommendations, it does not dictate your depth. Your depth should be dictated by the conditions and your skill level.
Recommended Depth Limits: All students, after
certification, should be advised to dive within depth
limits taught during class.
Recommended depth limits, based on the certification
levels, are as follows:
Scuba Diver - 40 feet (12 metres)
Junior Scuba Diver - 40 feet (12 metres, only with a
Dive Professional)
Open Water Diver – 60 feet (18 metres)
Junior Open Water Diver – 60 feet (18 metres, after
certification with no additional training)
Advanced Adventurer – 100 feet (30 metres, when a
Deep Dive was used in the program)
Junior Advanced Adventurer - 70 feet (21 metres)
Deep Diving Specialty Diver –130 feet (40 metres)