Dive Planning

Dive planning is where everything comes together: tide, weather, current, gas, decompression, navigation and communication become one coherent plan. "Plan the dive, dive the plan" is not a cliché but the core of safe diving. The goal is simple: no surprises. Everything you could meet underwater, you have thought through at the water's edge and given an answer.

A good plan answers four kinds of question. What are you going to do (goal, dive type, depth, time)? Where and when (site, conditions, tide, weather)? With what (gas, equipment, reserves)? And what if (emergency scenarios, lost buddy, surface problem)? That last category — the "what if" — separates a real diver from someone who only plans the fun half. Accidents rarely arise from one big thing, but from a chain of small things nobody had a plan for.

Plan the dive, dive the plan. You make the plan at the surface, with a clear head, not underwater where narcosis, stress and time pressure cloud your judgement. Underwater you execute the plan; you do not re-plan on the spot, except to become more conservative (shallower, shorter, turn around). Deviating is always allowed towards the safe side, never towards more risk.

Key concepts

Term	Short definition	Why it matters
Dive plan	Pre-considered whole of what, where, with what, what if	Prevents surprises underwater
Goal/dive type	What you want to achieve (reef, wreck, photo, training)	Steers all other choices
Site assessment	Evaluation of the site and conditions	The basis of the go/no-go
Depth/time limit	Max depth and time (NDL, gas, level)	Keeps you within safe limits
Gas plan	Usable gas, turn pressure, rock bottom	Ensures you return with a reserve
Role division	Who leads, navigates, shoots the DSMB	Prevents confusion in the team
Entry/exit plan	How you get in and out of the water	Often the riskiest part
Emergency plan	What to do when problems arise	The "what if" that saves lives
Briefing / debriefing	Discussion before and after	Aligning and learning
Logbook	Recording of the dive	Experience, planning the next dive, safety

Understanding dive planning

Step 1 — What: goal, type and limits

Start with the goal, because it steers everything. A relaxed photo reef dive, a deep wreck, a navigation training and a drift dive each need a different plan. Fix the type and goal of the dive; the maximum depth (set by goal, level, gas, NDL and, on nitrox, the MOD); the maximum time (set by the NDL and by your gas — the shorter of the two wins); and the turn criteria (at what pressure — turn pressure — and at what time/NDL you turn around). The golden rule: your dive is bounded by whichever runs out first, gas or no-decompression time. Calculate both and take the stricter.

Step 2 — Where and when: site and conditions

Here the environment topics come together. Assess the tide (plan around slack on current sites; check access at high/low water); the weather (wind force and direction, thunderstorm risk, timing within the day); the current (expected direction/strength, drift or fixed site, negative entry needed?); the waves (surf at entry/exit, surge on shallow parts); and the visibility and temperature (which set your navigation method and insulation/consumption). This assessment leads to your first go/no-go: do the conditions match your goal, level and team?

Step 3 — With what: gas, equipment and reserves

Translate your consumption and reserves into concrete numbers: usable gas and turn pressure calculated with your RMV; rock bottom determined at the deepest point, for two divers; the gas choice (air or nitrox, with a MOD check); the redundancy to match the dive (octopus, pony, doubles); and the equipment (DSMB and spool on current/boat dives, light when deeper/overhead/night, suitable insulation, cutting tool, signalling devices). A handy memory aid for the kitting-up order and the buddy check remains BWRAF: BCD, Weights, Releases, Air, Final check.

Step 4 — What if: the emergency plan

This is the part most beginners skip and the one that matters most. Discuss in advance, concretely: lost buddy (search about one minute, then a controlled ascent and reunite at the surface); out of air (who shares air how, octopus position known, then ascend together); surface problem (DSMB, whistle, how to signal the boat); too much current/downcurrent (swim away from the wall, drift-abort plan); illness/DCS symptoms (oxygen, call for help, DAN number); and abort criteria (at what observations do you end the dive — cold, stress, out of plan, equipment problem?). Every "what if" has a pre-agreed answer. That is the essence of safe diving.

A dive plan is like a pilot's flight plan: not only the route, but also the alternates, the fuel margin and the emergency procedures. Pilots practise "what if the engine fails" a thousand times on the ground so that in the air it is a reflex. Divers do exactly the same with "what if the air runs out".

The briefing: sharing the plan

A plan in one head is not a team plan. The briefing (by the guide or team leader) makes it shared. A good briefing covers, briefly and structured: site and goal; route, depth, time and turn points; conditions (tide, current, waves, visibility, temperature); gas and reserves (turn pressure, rock bottom, who watches what); team and roles (who leads, navigates, DSMB, buddy pairs); signals (hand, animal, emergency, surface); entry and exit (how in, how out, negative entry?); the emergency plan (lost buddy, out of air, surface, abort criteria); and finally questions — is everyone agreed? go/no-go.

The go/no-go decision

All steps come together in one decision: go or not? This is a team decision, and everyone has a veto. Do the conditions match goal and level? Does the gas plan add up? Is everyone fit, rested and agreed, with no doubt? Are entry/exit and the emergency plan clear and feasible? Only when all answers are favourable do you go and dive the plan. Remember: any diver can call any dive at any time for any reason. Doubt is a valid reason.

The debrief and the logbook

After the dive you close the loop. The debriefing briefly discusses what went well and what could be better: did the plan hold, were there surprises, what do you learn for next time? This is how teams improve. The logbook records the dive: date, site, max depth, time, gas consumption (for your RMV), conditions, buddy, notes. A logbook is not only a memory but a planning instrument: it helps you know your own consumption and behaviour, and it is proof of experience for further training and some dive centres.

Scenario. A team plans a drift dive in Indonesia properly: tide around slack, negative entry agreed, DSMB carrier assigned, turn pressure and rock bottom calculated, lost-buddy procedure repeated. Underwater one diver briefly loses the reef in the current; because the lost-buddy plan was discussed in advance, they search one minute, ascend in a controlled way, shoot their DSMB and are picked up by the boat within minutes. What could have been an incident was a non-event, purely thanks to the planning.

Real-world examples

The Netherlands (shore dive, tide and visibility). Planning turns on the tide table (slack, access), cold water (insulation, consumption), poor visibility (compass navigation, close to the buddy) and an often awkward entry/exit by a dike. The emergency plan and entry/exit get extra attention here.

Egypt (liveaboard, multiple dives). Planning per day: deep-to-shallow, surface intervals, nitrox for bottom time, and the flying wait on the last day. The per-site briefing by the guide is the norm.

Indonesia (drift, deep). Current and depth dominate: slack, negative entry, DSMB, turn pressure calculated on the hardest exertion, and a clear drift-abort plan.

Maldives (drift, repetitive). Tide-driven channel dives with many repetitive dives; planning intervals, gas and DSMB use in current is central.

Mozambique (Tofo and Vilanculos). At Tofo the plan integrates almost everything: tide (surf-launch timing), weather (wind for the launch), current and surge on the offshore reefs, negative entry from the RIB, gas for 20-30 m with reserve for the DSMB, and the flying wait because you fly home from a remote destination. At Vilanculos the emphasis is on tide around the Bazaruto sandbanks (access, current, visibility) and on shallower, more economical profiles, with the same flying wait. Both are textbook examples of how all the preceding topics come together in one plan.

Common mistakes

Mistake	What goes wrong	How to avoid it
Planning only the "fun half"	No answer to emergency scenarios	Always work out the "what if"
Not sharing the plan with the team	Confusion and separate actions underwater	Give/follow a structured briefing
Depth/time on feel instead of calculated	Beyond NDL or out of gas	Calculate NDL and gas; take the stricter
Not factoring conditions into the plan	Caught out by tide/weather/current	Do a site assessment
"Extending" the plan underwater	Going beyond safe limits	Deviate only towards the safe side
Ignoring doubt to keep up with the group	An unwanted, unsafe dive	Any diver can call any dive
No debrief/logbook	Not learning, RMV unknown	Debrief briefly, log every dive

Pro tips

• Plan with the four questions: What, Where and when, With what, What if. Never skip the "what if".
• Let the stricter limit win: gas or NDL, the shorter decides your dive.
• Give or demand a structured briefing; an unshared plan is not a team plan.
• Set turn pressure and rock bottom in advance and hold to them strictly.
• Underwater, deviate only towards the safe side (shallower, shorter, turn around), never towards more risk.
• Debrief briefly and log every dive; it improves your next plan and your RMV.

Frequently asked questions

What does "plan the dive, dive the plan" mean, and when may you deviate? You make the plan at the surface with a clear head and execute it underwater without re-planning, except towards the safe side (shallower, shorter, turn around). You never deviate towards more risk.

Which four questions does every dive plan answer? What (goal, depth, time), Where and when (site, conditions, tide, weather), With what (gas, equipment, reserves), and What if (emergency scenarios).

What bounds your maximum bottom time, and how do you choose? Your NDL (decompression) and your gas. Calculate both and take the stricter (shorter) as the limit.

Name three parts of a good briefing. For example: site and goal; route, depth, time and turn points; conditions; gas and reserves; team and roles; signals; entry and exit; emergency plan.

Why can any diver call any dive? Because safety comes before group enjoyment and doubt is a valid reason. "Any diver can call any dive at any time for any reason" prevents anyone diving unsafely to avoid disappointing the group.

Summary

Dive planning brings all the preceding topics into one plan you have fully considered before entering the water, with the goal of no surprises. Every plan answers four questions: What you are going to do (goal, depth, time, where the shorter of NDL and gas sets your limit), Where and when (site and conditions: tide, weather, current, waves, visibility, temperature), With what (gas, turn pressure and rock bottom calculated with your RMV, gas choice with MOD, redundancy and equipment), and What if (lost buddy, out of air, surface problem, downcurrent, DCS, and abort criteria). The "what if" matters most and is most often skipped. You share the plan through a structured briefing, because an unshared plan is not a team plan, and you take a go/no-go decision in which any diver can call any dive without explanation. Underwater you execute the plan and deviate only towards the safe side. Afterwards you close the loop with a brief debrief and a logbook, which improves your next plan and maps your own consumption and behaviour. This makes planning a fixed habit, on every dive, even the hundredth on the same reef.

The 10 things every diver should know by heart

1. Plan the dive, dive the plan; deviate only towards the safe side.
2. Plan with the four questions: What, Where and when, With what, What if.
3. Never skip the "what if"; emergency scenarios have a pre-agreed answer.
4. The stricter limit wins: gas or NDL, the shorter sets your bottom time.
5. Factor in conditions (tide, weather, current, waves) with a site assessment.
6. Calculate turn pressure and rock bottom in advance and hold to them.
7. Share the plan through a structured briefing; unshared is not a team plan.
8. Any diver can call any dive, without explanation; doubt counts.
9. Underwater, deviate only towards the safe side (shallower, shorter, turn around).
10. Debrief briefly and log every dive; it improves your next plan and your RMV.