Why should I keep a dive logbook?

A dive logbook helps document your diving experience, is required for certifications, and helps improve safety and planning.

Are digital logbooks better than classic ones?

Digital logbooks offer convenience and auto-sync, but many divers prefer classic logbooks for their personal touch and stamps.

Do I need a logbook for fun dives?

While not mandatory, a logbook helps track progress, and our team supports you with site names and stamps aboard our dive boat.

The Dive Logbook – Why It’s Important and What to Record

A dive logbook is more than just a collection of memories – it’s an essential part of your dive training and progress as a diver. Many divers, especially beginners, often ask: Why should I keep a logbook and what should I record in it?

Why a Dive Logbook Is Important

Your logbook documents all your dives, shows your experience, and helps when taking advanced courses or doing special dives. Some courses, such as Rescue Diver (min. 9 dives), Divemaster (min. 40 dives to start DM training), Instructor (min. 100 dives), or Solo Diver (min. 100 dives), require a minimum number of logged dives. A logbook may also be required when renting dive equipment.

What Should Be Recorded in a Dive Logbook?

Date and Location: When and where did the dive take place?
Dive Site: On our boat, you’ll always find the day’s dive sites listed on the blackboard at the coffee station.
Depth and Duration: How deep did you dive and for how long?
Air Consumption: Start and end pressure of your tank. (How to calculate air consumption?)
Gas / mix: Air or Nitrox (EAN) — if Nitrox, write the O₂ percentage (e.g. 32% / EAN32). Makes it easier to compare gas use and plan similar dives. (What is Nitrox?)
SAC rate (optional): Surface air consumption in L/min — worth logging to spot habits and track progress. You can estimate it from your logbook numbers on this page.
Weighting (lead): How much lead you used in kg — makes it easier to dial in the right weight for similar conditions, exposure suits, and tanks.
Equipment notes (optional): e.g. BCD size, wetsuit shorty vs. long, thickness (mm), boots — a useful extra when you rent gear or travel and want to remember what fit and buoyancy felt right.
Buddy and Instructor: Who did you dive with?
Highlights: Marine life seen, currents, wrecks, etc.
Stamp and Signature: Especially important for training dives.

SAC rate from your logbook numbers

Your logbook usually lists gas used (start/end pressure), time, and often max depth. To turn that into a SAC (surface air consumption) in L/min, the formula uses average depth — not everyone writes that down. If you only know max depth, you can estimate average depth as about 60% of max depth for typical Koh Chang reef dives (multi-level profiles). If your computer shows average depth, enter it instead for a more accurate result.

Why calculate and log it? Working out your SAC and writing it in your logbook (even just now and then) helps you notice patterns—how depth, currents, workload, or a stressful day affect your breathing—and see real progress when your numbers improve over time.

⚠️ Note: This tool is for learning and logbook math only. The 60% rule is a rough estimate — actual average depth depends on your profile. Always follow your dive computer and training.

📊 SAC rate calculator (logbook)

Gas used (bar)

Time (minutes)

Tank size (L)

Max depth (m)

Avg depth (m), optional

If average depth is empty, we use 60% × max depth (Koh Chang-style estimate). If you enter average depth, we use that value.

Enter gas used, time, tank size, and depth.

Full gas planning tools (MOD, best mix, etc.): Gas consumption & SAC on Koh Chang.

Digital Logbook vs. Classic Logbook

Today, many divers keep digital logbooks using apps like Divelog, SSI, or PADI. Modern dive computers often have Bluetooth features that automatically transfer your dives to your smartphone, making digital logging almost effortless. Even older dive computers can store up to 999 dives. Still, many divers love their classic logbooks as a personal keepsake.

Looking for a dive computer with automatic logging? Compare the best models with Bluetooth sync and app integration: Best Dive Computers 2025 – Suunto D5, Garmin MK3i & Shearwater TERIC

Who Fills Out the Logbook?

During courses, your instructors and divemasters help you fill out and stamp your logbook. For fun dives, you’re responsible for your own logbook, but our team is always ready to assist.

Fun divers who still keep a classic logbook can find the dive site names and the stamp at the coffee station on our boat. Once everything is filled out, they can get their guide’s signature. During courses, instructors explain and assist with completing the logbook.

Printable logbook page (PDF, A5 format)

Run out of pages or forgot your logbook? Download a single A5-format page to print and fill in by hand — handy before a trip or after a full logbook. In the print dialog, choose paper size A5 (or scale to fit).