Sports & Outdoors

Bottomtime

Dive Logbook

Log every dive in seconds and keep your data, wherever you dive.

Bottomtime is an offline-first dive logbook for iPhone and iPad, made by Develak for recreational and technical divers, freedivers, and snorkelers who want to own their dive data.

Age
4+ years old
Category
Sports
Price
Free In-app purchases
Languages
44 EN · FR +42
Requires
iOS 17+ iPhone · iPad
Size
6.4 MB
Version
1.0

Overview

What is Bottomtime?

Bottomtime is the dive logbook you can open on a boat, a liveaboard, or in a cenote with no signal at all. Enter a dive in the “Quick Log” screen in about 30 seconds, or switch to the detailed editor when you have more time, and watch your personal “Dive Sites Map” fill up with every place you’ve been underwater.

The free version already includes an unlimited dive log with photos, career stats, and a “Species Log” for marine sightings, with names never held back for a paid tier. Bottomtime Pro adds automation on top, from importing data out of Apple “Health” and dive computers to automatic iCloud sync across iPhone and iPad, without changing how your data is stored or exported.

Read the full App Store description

Bottomtime is the dive logbook that belongs to you — beautiful, fast, and offline-first. Log a dive in 30 seconds, watch your sites map fill up, and keep your whole diving life in one place. No account required. Your data is yours.

Why divers switch to Bottomtime

  • Offline-first: log on the boat, the liveaboard or the cenote — no signal needed. Everything syncs when you’re back.
  • Log a dive in 30 seconds: site, depth, time, gas, buddy, conditions — fast, or as detailed as you like.
  • Your sites on a map: every dive plotted, your personal underwater passport.
  • Species log included — names and sightings are never behind a paywall.

Free, and generous

  • Unlimited dive log with photos
  • 30-second quick log and a full detailed editor
  • Career stats: dives, max depth, total bottom time
  • Dive sites map
  • Marine species log with common names

BOTTOMTIME PRO — automation and comfort, never your data

  • Import from Apple Health and dive computers (depth, duration) — no double entry
  • Import and export open formats: UDDF, CSV, PDF
  • Automatic iCloud sync across iPhone and iPad
  • Advanced stats and trends: SAC/RMV, average depth, progression over time
  • Gear tracking with service reminders
  • Species photos and history
  • PDF logbook export with instructor signature
  • Surface interval and no-fly planner (informational)
  • Home Screen widgets

Built for every diver

Recreational, technical, freediver or snorkeler — multi-cylinder, nitrox and trimix, safety stops, and metric or imperial units.

Your data, your rules

No account needed. Works fully offline. Export to UDDF, CSV and PDF anytime — your dive history is never locked in.

Premium is available as a monthly or yearly subscription (with a 7-day free trial on the annual plan) or a one-time lifetime unlock. Free features stay free, forever.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://develak.com/privacy-policy/

Highlights

What can you do with Bottomtime?

Log dives in 30 seconds, map your sites, and track marine species with Bottomtime, the offline-first dive logbook by Develak for iPhone and iPad.

Quick Log in About 30 Seconds

Enter site, depth, time, gas, buddy, and conditions in the “Quick Log” screen right after you surface.

  • Personal Dive Sites Map

    Every logged dive is plotted on your “Dive Sites Map”, building a personal underwater passport.

  • Species Log Included Free

    Record marine species sightings with common names in the “Species Log”, part of the free experience.

  • Offline-First Logging

    Log dives with no signal on a boat, a liveaboard, or in a cenote, then let everything sync once you’re back online.

  • Import From Apple Health and Dive Computers

    With Bottomtime Pro, bring in depth and duration from Apple “Health” and compatible dive computers instead of entering it twice.

  • Gear Log With Service Reminders

    Keep an equipment log and get reminders when service is due, part of Bottomtime Pro.

Who it’s for

Who is Bottomtime for?

  • Recreational divers

    Log dives after every trip in the “Quick Log” screen and watch your “Dive Sites Map” grow with each destination.

  • Technical divers

    Track multi-cylinder configurations, nitrox and trimix mixes, and safety stops in the same logbook as your recreational dives.

  • Freedivers and snorkelers

    Keep a personal record of dives and species sightings in the “Species Log” without any scuba-only assumptions.

  • Divers who want to own their data

    Skip the account, work fully offline, and export your logbook to UDDF, CSV, or PDF whenever you like.

How it works

How does Bottomtime work?

From “Log a dive” to “Unlock Bottomtime Pro”, in 4 steps.

  1. Log a dive

    Open Bottomtime after surfacing and fill in site, depth, time, gas, buddy, and conditions in the “Quick Log” screen.

  2. Watch your map fill up

    Each logged dive appears on your “Dive Sites Map”.

  3. Add species sightings

    Record marine species you spotted, with common names, in the free “Species Log”.

  4. Unlock Bottomtime Pro

    Import depth and duration from Apple “Health” or a dive computer, sync across iPhone and iPad with iCloud, and export a PDF logbook with instructor signature.

In depth

Bottomtime, in detail

How does the “Quick Log” screen work in Bottomtime?

The “Quick Log” screen asks only for the essentials — site, depth, time, gas, buddy, and conditions — so you can log a dive in about 30 seconds right after surfacing.

When you have more time, the same dive can be opened in the detailed editor to add extra notes, without slowing down the quick entry option for your next dive.

What does the free “Species Log” include?

The “Species Log” lets you record marine species sightings by common name for every dive, and it stays part of the free version of Bottomtime.

With Bottomtime Pro, you can also add photos to each species entry and build up a history of your sightings over time.

How does Bottomtime handle dives logged without a signal?

Bottomtime is offline-first, so you can log dives on a boat, a liveaboard, or in a cenote with no connectivity at all.

With Bottomtime Pro, automatic iCloud sync brings everything you logged offline across to your other device once you’re back online.

Release notes

What’s new in Bottomtime

Version

1.0

This is the first version of Bottomtime, released on June 22, 2026.

Is Bottomtime free?

Yes. Bottomtime is free to download from the App Store. Optional in-app purchases unlock extra features; they are billed by Apple to your Apple Account, and you can manage them at any time in your account settings.

Which devices does Bottomtime work on?

Bottomtime works on iPhone and iPad with iOS 17.0 or later.

How do I log a dive quickly in Bottomtime?

Use the “Quick Log” screen to enter site, depth, time, gas, buddy, and conditions in about 30 seconds, then add more detail later in the full editor if you want.

Do I need an account to use Bottomtime?

No. Bottomtime works without any account, so you keep full control of your dive data from the start.

Can I use Bottomtime with no internet connection?

Yes. Bottomtime is offline-first, so you can log dives with no signal and everything is saved for whenever you next have a connection.

Does Bottomtime support technical diving?

Yes. You can log multi-cylinder setups, nitrox and trimix, and safety stops alongside recreational dives, in metric or imperial units.

Can I export my Bottomtime logbook?

Yes. You can export your logbook to UDDF, CSV, or PDF at any time, so your dive history is never locked into the app.

What does the surface interval and no-fly planner do in Bottomtime Pro?

It’s an informational planner that helps you think through surface intervals and no-fly timing; it is not a certified dive computer or safety instrument.

What languages is Bottomtime available in?

Bottomtime is available in 44 languages: Arabic, Bangla, Catalan, Chinese (Simplified), Chinese (Traditional), Croatian, Czech, Danish, Dutch, English, Finnish, French, German, Greek, Gujarati, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Kannada, Korean, Malay, Malayalam, Marathi, Norwegian Bokmål, Odia, Polish, Portuguese, Punjabi, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Tamil, Telugu, Thai, Turkish, Ukrainian, Urdu and Vietnamese.

How do I get help with Bottomtime?

Visit the Bottomtime support page: it answers common questions about purchases, sync and settings, and has a contact form. You can also write to contact@develak.com. We read every message and reply personally.

Made by Develak

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