The Logbook
Long-form guides built on the same data as the map: which wrecks, animals and shore entries are worth the trip, and when. Written from published sources, with every claim linked.
50 guides, newest first
Trip planning
Every area we cover is rated for each month of the year. Read across the whole map, the year has a shape nobody publishes: a summer plateau when the Mediterranean, the Atlantic and the cold-water coasts open together, and a November trough when almost everything is between seasons.
20 September 2026 · 13 min read
Trip planning
The shape of the diving year from our records: which seas open in each month, which close, and the places at their best from January to December.
20 September 2026 · 13 min read
Body & health
Where the bubbles form, where they lodge, the symptom ladder and its clock, and what a chamber actually does — drawn from a working decompression model.
12 September 2026 · 18 min read
Big animals
Where seals and sea lions come to divers, how deep and how hard each colony dive is, when each one runs, and why the pupping season is the wrong season.
12 September 2026 · 17 min read
Gear & kit
A closed-circuit rebreather uses the same oxygen at 60 metres as at 6. Here is the arithmetic behind that, what the loop actually buys, and what it costs.
9 September 2026 · 6 min read
Night diving
What blackwater diving is: drifting over thousands of metres of open ocean at night, on a tether or lit downline, as the largest migration on Earth rises past.
6 September 2026 · 13 min read
Body & health
How deep can you scuba dive? Every limit, computed: 18 m training, 33 m gas density, 40 m no-stop, 56.5 m air ceiling, then trimix, the 332 m record, the floor.
6 September 2026 · 13 min read
Gear & kit
A wetsuit thickness guide computed, not copied: the watts a 3, 5 or 7 mm suit leaks at each water temperature, at the surface and at 20 m, band by band.
6 September 2026 · 11 min read
Body & health
Why do I have to pee when diving? Water pushes up to 700 mL of blood into your chest, the kidneys dump the surplus — and the first reason you tire after.
6 September 2026 · 12 min read
Big animals
Corals, groupers, snappers and palolo worms all spawn on the moon's schedule. The calendar, the dives timed to it, and why it is so dangerously fishable.
5 September 2026 · 10 min read
Night diving
Most of the deep sea makes its own light, the flash is tuned to 476-nanometre blue — the colour seawater carries farthest — and any night dive can show it.
2 September 2026 · 7 min read
Ocean science
Water sorts itself into layers by heat and salt. Why lakes turn over at 4 °C, why haloclines blur your view, and the 2 kg buoyancy step a cenote hands you.
2 September 2026 · 8 min read
Ocean science
The tide is a wave with a 12.4-hour clock. Why slack belongs to the stream, not the height — and why an 8-knot channel gives you fifteen diveable minutes.
2 September 2026 · 7 min read
Body & health
Nothing down there hunts divers. Nearly everything that hurts is stationary, camouflaged and defensive — the injury happens when you tread, brush or grab.
2 September 2026 · 8 min read
Ocean science
Sea colour, computed: chlorophyll closes the blue window, the sunlit zone collapses from 124 m to 10, and the green water is where the food is.
1 September 2026 · 8 min read
Night diving
The night dives worth travelling for — Kona's manta feed, blackwater, mandarinfish at dusk, bioluminescence, coral spawning — and how each one is run.
31 August 2026 · 12 min read
Big animals
Where divers meet tiger, bull and great white sharks in 2026 — the sites that still run, the ones that closed, and what the feeding science shows.
31 August 2026 · 14 min read
Caves & caverns
Blue holes are drowned ice-age caves. The science of their layered water, the ones you can actually dive, and the record depths no human has visited.
31 August 2026 · 13 min read
Body & health
No-stop limits computed for a surface at 1,500 and 3,000 m, the Cross correction — and why the model in your dive computer was built for mountain lakes.
31 August 2026 · 7 min read
Big animals
Bali's sunfish are mostly a different species than the name suggests. Where sunfish diving is a real season — Nusa Penida, the Galápagos — and where it is luck.
31 August 2026 · 11 min read
Body & health
Where the 1.4 bar oxygen limit actually comes from: wartime trials, the NOAA exposure table, and a chosen margin below a threshold nobody can predict.
31 August 2026 · 13 min read
Body & health
What an hour on deck actually buys back, computed compartment by compartment — and how a 1956 bookkeeping convention became diving's most repeated rule.
31 August 2026 · 8 min read
Big animals
Swimming with whales is legal in only a handful of places, all of them snorkel and all of them permits. How each program runs, and where the answer is no.
31 August 2026 · 14 min read
Big animals
The world's only reliable daily thresher shark dive moved from Monad Shoal to Kimud Shoal in 2022. Where the sharks are now, and how the dive is run.
31 August 2026 · 11 min read
Ocean science
Wave physics for divers, computed: why wind chop dies by 7 m while a 14-second swell still moves you at 40, and why the safety stop is the roughest part.
31 August 2026 · 8 min read
Body & health
Three minutes at 5 m, computed compartment by compartment — what the stop changes, where the number came from, and when to skip it.
31 August 2026 · 11 min read
Body & health
Water takes body heat 25 times faster than air. Computed: what every breath costs at depth, and how a 5 mm wetsuit becomes a 2.9 mm suit at 30 m.
31 August 2026 · 8 min read
Gear & kit
What a wetsuit is really worth, why every cylinder swings by the weight of its air, and why the belt that felt right on the bottom fails at the safety stop.
28 August 2026 · 8 min read
Body & health
What a cabin at 8,000 feet does to you, what the decompression model says about it, and why DAN's 12 and 18 hours come from chamber trials, not arithmetic.
28 August 2026 · 8 min read
Body & health
Breathing gas density has a published limit most divers have never heard of. Air passes it at 33 metres, nitrox slightly sooner, and only helium moves it.
28 August 2026 · 8 min read
Gear & kit
Surface consumption, what depth does to it, the reserve two divers need to reach the surface, and why the cylinder rather than the computer ends most dives.
28 August 2026 · 9 min read
Ocean science
Water absorbs red light about 140 times more strongly than blue. What that does to colour as you go down, computed from the physics, and what a torch puts back.
28 August 2026 · 7 min read
Body & health
The pressure across your eardrum, the clinical thresholds in metres, every equalisation technique that works, and the point at which you call the dive.
28 August 2026 · 8 min read
Cold water
Ice, kelp forests, hydrothermal chimneys and 80 m of visibility — 55 cold-water dive sites from Antarctica to Tasmania, and what the drysuit costs.
27 August 2026 · 8 min read
Wrecks
Fifty-three wrecks past 30 metres, sorted by the depth they ask for: the recreational edge, the decompression band, and the trimix ground past 60 m.
27 August 2026 · 8 min read
Trip planning
Cost per dive, not sticker price: the cheap certification hubs, shore-diving islands and budget liveaboard regions where the diving is good, and the catch.
27 August 2026 · 15 min read
Freshwater
Springs, cenotes, alpine lakes, flooded quarries, river drifts and Great Lakes wrecks: where freshwater diving is a destination, and what changes without salt.
27 August 2026 · 15 min read
Body & health
Decompression made visible: tissue compartments, M-values, no-stop time and gradient factors, drawn live from a working Bühlmann ZH-L16C model.
27 August 2026 · 10 min read
Big animals
Thirty-nine whale shark sites, split into the aggregations you can book a date against and the seamounts where a sighting is luck, with the months for each.
27 August 2026 · 16 min read
Gear & kit
Every gas divers breathe: air, nitrox, trimix, heliox, hydreliox and rebreather diluents — what each one fixes, what it costs, and where the answer changes.
25 August 2026 · 15 min read
Big animals
Oceanic whitetips are dived in a handful of places, ten of them Egyptian or Sudanese. Where they are, why autumn concentrates them, and how the dive is run.
24 August 2026 · 11 min read
Drift & current
What a drift dive really asks of you, how to read a tidal pass before you get in, the three skills that matter, and 26 sites where the current is the dive.
22 August 2026 · 8 min read
Gear & kit
What a diver propulsion vehicle changes underwater, how to plan range and gas around one, the sites where it earns its place, and where scooters are banned.
20 August 2026 · 10 min read
Caves & caverns
Thirty-one overhead dives for recreational divers — cenotes, springs, sea caves and coral caverns — and the famous holes you should only look into.
17 August 2026 · 8 min read
Big animals
Twenty-two manta sites — cleaning stations, feeding channels and the Kona night dive — with the months each works and how to behave when a ray comes to look.
14 August 2026 · 8 min read
Macro & muck
The muck capitals — Lembeh, Ambon, Dauin, Anilao, Milne Bay — the temperate piers that rival them, what an hour over black sand turns up, and how to dive it.
12 August 2026 · 6 min read
Big animals
Twenty places where scalloped and great hammerheads are reliably seen, with the months each one works, the depth and current involved, and how the dives run.
9 August 2026 · 6 min read
Wrecks
The 49 Second World War wrecks in our guides that recreational and technical divers can visit, by theatre, with depth, level and the best months for each.
6 August 2026 · 7 min read
Trip planning
An honest comparison of liveaboard and resort diving: cost per dive, dives per day, who each suits, seasickness, non-divers, and where each one wins outright.
4 August 2026 · 6 min read
Shore diving
Sixty dive sites you walk into from a beach, a jetty or a flight of steps, from the Red Sea to Iceland, with depth, level and the best months for each.
1 August 2026 · 8 min read
First dives
What makes a wreck a good first wreck, what the dive feels like, what to leave for later, and 26 shallow, intact, easy-access wrecks in warm and cold water.
29 July 2026 · 6 min read
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Sourced. Each guide lists the published material it was written from — operator briefings, park notices, wreck registers, papers.
Checked. Every claim is checked against those sources before a guide goes out, and re-checked when the sources change.
Independent. No destination or site is a paid placement. How Reefwander works.