Nitrox is a breathing gas with a higher oxygen percentage than you find in air. As a consequence, you breathe less nitrogen during your dive. This in turn allows for longer dives at the same depth, compared to breathing air at the same depth. The additional oxygen does have consequences. This is why a course in the use of Nitrox is required before you can take benefit of the longer bottom times. To take the course you must be 12 years old or older. You must also be a certified diver or be a student in an Open Water Scuba Diver course. The course can be completed in a day.

Your instructor will want a completed medical statement from you. In some regions a medical statement with only “no” answers will be sufficient for participation in the course. In other regions a medical signed and stamped by a medical doctor will be required and must unconditionally say that you are fit for diving.

You start this course by downloading the book and reading it. After you have finished a chapter, you can test your knowledge by doing a small 10 question test. Bring your answers to your SCUBA C&P Instructor to have them corrected. Your instructor will then explain all missed answers to assure that your understanding of diving theory is adequate. For some assignments you require a dive table.

Quiz11 Quiz21
Quiz12 Quiz22

37If you prefer to read your book on paper, then ask your instructor. The price for the paper version of this book is €9.90. If you cannot find a SCUBA C&P instructor in your area, then please contact us via

Your instructor has more questionnaires available if you wish to practice more. To complete the theory part of the course, you will have to pass an exam under the supervision of your instructor. The minimum score for passing is 80%.