How to Log a Dive

A dive log is your personal record of every dive you do. It helps you track your experience, spot patterns in how you use your gas, fine-tune your weighting, and remember the places and animals you've seen. Many dive centres and training agencies also ask to see your logbook before a course or a guided dive.

This guide covers what to record after each dive. It applies to any logbook — paper, a dive computer's own history, or an app like DiveHub — so you can start good habits from your very first dive.

Log it soon after the dive

Fill in your log as soon as you can, ideally within an hour or two. Details like how much weight felt right, what the current was doing, or which fish you saw fade quickly. If you dive with a computer, much of the numeric data is recorded for you, but it's still worth checking it and adding the things the computer can't know.

1. The basics: date and place

Start with the context of the dive:

• Date of the dive.
• Dive site name and location, for example the reef, wreck or shore entry point and the nearest town or country.
• Dive centre or buddy, if you dived with one, so you can find them again.
• Dive number, counting up from your first dive. Many logbooks do this for you.

2. Dive time

Record how long you spent underwater, and when:

• Entry time and exit time, or the time of day you started.
• Bottom time (also called dive time): the time from leaving the surface to starting your final ascent. Check how your dive computer defines it, as the definition varies slightly between brands.
• Surface interval: the time spent on the surface since your previous dive. This matters for planning repeat dives.

Over time, your total logged dive time is a simple measure of your experience.

3. Depths

Record two numbers:

• Maximum depth: the deepest point you reached.
• Average depth: the average across the whole dive. Your dive computer usually calculates this for you.

Depths are recorded in metres or feet. Whichever you use, stay consistent so your entries are easy to compare.

It's also worth noting the water temperature at depth and at the surface, and the visibility, as these shape how the dive felt.

4. Gas consumption

Tracking your gas use is one of the most useful things you can do as a new diver. It shows how your breathing improves with experience and helps you plan safe dives.

Record:

• Gas mix: air, or nitrox with its oxygen percentage (for example EAN32).
• Tank size (for example 12 L or 80 cu ft) and material, if you use more than one type.
• Starting pressure in bar or psi.
• Ending pressure in bar or psi.

The difference between the two pressures is how much gas you used. When you know your tank size, you can work out your surface air consumption (SAC) rate — how much gas you use per minute at the surface equivalent. A falling SAC rate over your first dozen dives is a good sign that you're relaxing and breathing more efficiently.

5. Weights

Getting your weighting right makes diving easier, safer and more comfortable. Note down:

• Total weight carried in kilograms or pounds.
• Exposure protection worn: for example a 3 mm shorty, a 7 mm wetsuit or a drysuit.
• Water type: salt or fresh. Salt water is more buoyant, so you need more weight.
• Tank type: aluminium tanks get lighter as you breathe gas and become more buoyant than steel tanks.
• How it felt: were you too heavy, too light, or just right at your safety stop with a nearly empty tank?

Comparing these entries across dives lets you find your ideal weighting for each combination of suit, tank and water.

6. What you saw

This is the part that makes a logbook worth reading years later. Write down:

• Marine life: fish, turtles, sharks, rays, corals, nudibranchs — whatever you spotted. Don't worry if you don't know the names; describe it and look it up later.
• Features of the site: a wall, a swim-through, a wreck's cargo hold, a cleaning station.
• Conditions: current strength, surge, visibility, and weather above the water.
• Highlights and lessons: what you enjoyed, what you'd do differently, and anything to remember for next time.

Photos and sketches are a great addition.

7. Verification and sign-off

On a paper log, divers traditionally have an instructor, divemaster or buddy sign or stamp each dive. This verifies the entry and is often required for certifications. Digital logbooks may let you attach a buddy or instructor instead.

Quick checklist

Tips for new divers

• Log every dive, including training and shallow dives. Consistency matters more than detail.
• Be honest. Accurate records, including mistakes such as arriving at the surface with little gas, are the most useful for improving.
• Let your dive computer help. Import its data rather than retyping it, then add the personal details yourself.
• Keep a backup. Photograph paper pages or use an app that stores your log online.

Log your dives in DiveHub

Once you know what to record, DiveHub makes it quick. See Logging Dives to add a dive by hand, or Importing Dives to bring in data from your dive computer.