How Long Is a Scuba Dive? Typical Dive Times and What Limits Them

How long does a typical scuba dive last?

Somewhere between 30 and 60 minutes, counting the whole time underwater. PADI says most recreational dives last between 30 and 50 minutes and that the figure varies with how fast you breathe. Dive operators tend to schedule for the top of that range. Emperor Divers says a typical Red Sea dive with its boats lasts about 60 minutes. Wallacea Dive Cruises in Indonesia lists an average of 60 minutes for regular dives and 45 for night dives.

Some operators write the number into their rules. Aquaventure in the Maldives states that dive time can be no longer than 60 minutes and that decompression dives are not allowed. Its night dive is capped at 45 minutes.

So when a boat briefing says "60 minutes", that is usually the ceiling, and many divers surface before it. Your own number comes from your tank, your breathing rate and the depth. Our tank duration calculator gives it for your gear before you book.

What ends a scuba dive?

One of four limits, and whichever arrives first wins. On any given dive only one of them is usually close.

• Gas supply. You turn the dive when your cylinder reaches the pressure you planned to surface with. Deeper water empties the tank faster, because each breath is denser.
• The no-decompression limit (NDL). This is the longest time at a depth that still allows a direct ascent without mandatory stops. It shrinks quickly as you go deeper.
• Cold. DAN says most divers benefit from thermal protection in water cooler than 27°C (80°F) and that significant thermal stress can be expected below 24°C (75°F). BSAC's advice covers this: be prepared to abort the dive any time you are not happy about it.
• Rules. The operator's time cap, the guide's plan and your certification depth. PADI limits Open Water Divers to 18 m (60 ft) and Advanced Open Water Divers aged 15 and over to 30 m (100 ft).

Which limit ends the dive at 10, 18 and 30 m?

Gas in shallow water, the no-stop limit in deep water, and at 18 m it is close. The table puts the site's own numbers side by side. The gas column is for one diver with a 12 L tank filled to 200 bar, a surface air consumption (SAC) of 20 L/min and a 50 bar reserve, staying at a single depth, as worked out in our post on how long a scuba tank lasts. The no-stop columns come from the DECO 2000 table and Table 9-7 of the US Navy Diving Manual, compared in our no-decompression limits guide. DECO 2000 has no 10 m row, so a 10 m dive is read on the 12 m row, following the table's round-deeper rule.

At 10 m the tank runs dry long before either table would stop you, so a 45-60 minute shallow dive is gas-limited or capped by the operator. At 18 m the same diver has 32 minutes of gas against a 45-minute DECO 2000 limit; a calmer diver with a SAC of 15 L/min gets 42 minutes of gas, which is nearly level with the table. At 30 m the order flips. DECO 2000 allows 15 minutes and the Navy 25, while the tank would last 22.

Real dives last longer than the 18 m and 30 m rows suggest because nobody spends the whole dive at maximum depth. A typical boat dive drops to its deepest point first and then works shallower, where gas lasts longer and a dive computer gives back no-stop time. That is how a dive with an 18 m maximum reaches 50 or 60 minutes.

How long is a try dive or a course dive?

Shorter than a normal fun dive. A try dive is usually 20-30 minutes in shallow water. Dreamtime Dive & Snorkel, which runs Great Barrier Reef trips from Cairns, says its introductory dives last around 20-30 minutes, reach a maximum of 10 m and spend most of the time at 4-5 m. PADI's Discover Scuba Diving keeps the optional open water dive within 12 m (40 ft).

Course dives have minimum times rather than typical ones. SSI's standards say an individual open water training dive must last at least 15 minutes, including the entry, the exit and putting on and taking off the scuba unit. Its Open Water Diver course needs at least four open water dives and a total bottom time of at least 80 minutes. PADI's Open Water course also has four open water dives, usually over at least two days, with dives 1 and 2 limited to 12 m and dives 3 and 4 to 18 m.

Expect course dives to feel short, because part of each one is spent on skills with the instructor.

How long are dives on a liveaboard or a three-dive day?

About the same length each time, but the later dives are planned shallower, so the no-stop limit stays out of the way. Emperor Divers says most Red Sea liveaboard itineraries offer three to four dives a day. Aquaventure's day shows the pattern: dive 1 to a maximum of 30 m for 60 minutes, dive 2 to 25 m for 50 minutes, dive 3 back to 30 m for 60 minutes after the long afternoon break, and a night dive to 20 m for 45 minutes. Dreamtime offers up to three dives in a day with five hours of reef time.

Nitrogen from the earlier dive is the reason. On the DECO 2000 table a first dive to 18 m for 35 minutes ends in group E. After 1 hour 10 minutes on the boat, a second dive to 18 m has only 15 minutes of no-stop time left, against 45 on a fresh day. Plan the second dive to 15 m and it gets 35 minutes. Our post on repetitive dives and surface intervals walks through the lookups.

A dive computer does the same bookkeeping and credits the time you spent shallower, so its numbers differ from the table's. It still shrinks the second dive's limit, so on a four-dive day the deep dive belongs first.

Can nitrox or a lower air consumption make dives longer?

Yes, but each one fixes a different limit. Nitrox lengthens the no-stop limit. DAN explains that breathing less nitrogen is the equivalent of breathing air at a shallower depth, and gives the example of 32% nitrox at 110 ft (34 m) being equivalent to air at 90 ft (27 m). That pays off on the 30 m row of the table above, where the NDL ends the dive. At 10 m it changes nothing, because the tank was always going to run out first. Our post on whether nitrox is worth it has the minutes by depth and mix.

A lower SAC rate stretches the gas, which helps on the shallow and middle rows. At 18 m with the same 12 L tank, a diver with a SAC of 15 L/min has 42 minutes before the reserve and a diver at 25 L/min has 25. A bigger tank does the same job for the gas limit but not for the NDL.

Neither changes the operator's 60-minute cap. On a guided boat dive that cap is often the real limit for a calm diver in shallow water.