Scuba diving and flying have been seen as problematic when they go together ever since the invention of flight itself. The obvious difference between the pressure and strain that your body has to deal with in each case often requires, therefore, a certain period of time and a few precautions for the purpose of safety, both before and after diving.
The first thing you have to keep in mind when it comes to scuba diving and flying is to keep yourself above the surface for up to 12-24 hours after a long flight, especially if you are fatigued, you had to fly through several time zones, or are planning multiple, strenuous dives. Experts don’t necessarily agree on the actual time you have to wait before scuba diving is safe. This is largely due to the fact that there are several factors involved, including the inset of fatigue and disorientation, jet lag, improper nourishment or stress. Since flight affects each person differently pertaining to these criteria, it will likely take some people longer to recover, while others may be ready for a dive sooner. Generally, physical fitness and being used to flight can influence many of the aforementioned factors; however, the main recommendations are to wait about 12 hours if you only plan a single dive, and up to 18-24 hours if you’re planning multiple dives.
Beginners who are not accustomed to flight or to scuba diving might find they are still fatigued, stressed or feeling bad even after the 12-24 hour period of rest designated before the dive. In such cases, it is extremely important for that person to be aware of their physical condition and take a few precautions. Make sure you rest well and receive proper nourishment before you go diving. Also, flight travel can leave some people dehydrated, so keep a few bottles of clean, mineral water close by, so that you can restore your water reserves. Even after taking these precautions, scuba diving and flying should not be taken for granted as being completely safe. Make sure you and your diving partners assess your condition properly each time.
Going straight to high altitude from diving is the same issue associated with getting out of the water too quickly: the diver is subjected to an environment with reduced pressure that can lead to excess nitrogen still present in the blood coming out as bubbles. The body, therefore, has to adapt to the new conditions gradually, and so the diver would need a period of at least 24 hours before boarding a flight after the last dive is finished. Anyone considering scuba diving and flying should keep these recommendations in mind, in order to avoid problematic health-related complications.