In the last week of September I took de Open Water course at Big Blue. We did 4 dives and had practice morning in the pool. Unfortunately it's mandatory to watch a couple of videos and do some homework, but other than that I had a great time. Lily was our instructor and she did a great job! While having a lot of fun with us she was at the same time a great instructor and made sure everyone was comfortable and knew what they were doing. Two days after finishing the Open Water course I came back to Koh Tao and Big Blue to do the Advanced Adventurer course as well. This time Sonia was our instructor and she was equally good fun and committed to making sure we were having a great time. Although the advanced course consisted of 5 more dives and several skills, such as navigation and a night dive, I did not really feel like I learnt that much, except for gaining more experience. It would be great to work a bit more on breathing and swimming techniques. Nevertheless, I would highly recommend Big Blue and might be back in the future!