Oceanic Pro Plus 4.0 Dive Computer: Specifications and Who It Suits
The Oceanic Pro Plus 4.0 is a expert tier dive computer at $850 to $1,000, running Dual algorithm, Pelagic DSAT or Pelagic Z+ with a large segment lcd with backlight and included air integration, accepting nitrox mixes up to 100 percent. Instructors and divemasters who want compass, depth and pressure in one hand.
The Oceanic Pro Plus 4.0 is a expert tier dive computer in the $850 to $1,000 band. A big console with an integrated compass and a quick disconnect. Heavy and expensive for what it is, and the easiest to read of anything in a console form factor.
The specifications below are the manufacturer's published figures. Where we could not confirm a figure against the maker's own documentation, the row is left out rather than guessed at, which is why some units on this site show fewer rows than others. On a page whose readers can check the work, a missing row is better than an invented one.
What are the Oceanic Pro Plus 4.0 specifications?
| Specification | Pro Plus 4.0 |
|---|---|
| Brand | Oceanic |
| Model | Pro Plus 4.0 |
| Decompression model | Dual algorithm, Pelagic DSAT or Pelagic Z+ |
| Maximum oxygen fraction | 100 percent |
| Air integration | Included |
| Display | Large segment LCD with backlight |
| Battery | Rechargeable |
| Depth rating | 100 m (328 ft) |
| Modes | Air, Nitrox, Gauge, Freedive |
| Trimix | No |
| Closed circuit | No |
| Price band | $850 to $1,000 |
| Tier | Expert |
Who is the Pro Plus 4.0 for?
Instructors and divemasters who want compass, depth and pressure in one hand.
An expert tier computer buys capability at the edges: trimix, closed circuit support, multiple transmitters, or a screen legible in conditions that defeat everything else. Very little of that is touched by a recreational profile. Buying one is defensible if you are heading toward technical training or you dive in conditions where legibility is the binding constraint, and hard to justify otherwise.
Who should not buy the Pro Plus 4.0?
Travel divers. It is bulky, and a wrist computer plus a small gauge weighs far less.
That is the more useful half of any specification page. Computers in this category are close enough on the things that matter, tracking depth and time and applying a model, that the deciding factor is usually a mismatch rather than a ranking: a screen you cannot read without glasses, a menu system nobody near you can teach, or a feature set aimed at diving you do not do. Compare against the alternatives at the bottom of this page before deciding.
What does Dual algorithm, Pelagic DSAT or Pelagic Z+ actually mean on a dive?
A decompression model is a mathematical description of how quickly inert gas moves into and out of body tissue, used to calculate how long you can stay at a depth before a direct ascent stops being acceptable. Every computer runs one, they disagree with each other, and the disagreement is real rather than cosmetic.
Pelagic DSAT descends from the data behind the recreational dive planner tables and sits at the liberal end of the models in common use. It will show longer no-stop times than a conservative RGBM implementation on the same profile. That is not a fault, but it is something to know before you dive alongside a buddy on a different brand, because the pair of you will be looking at meaningfully different numbers and the dive should be run on the more conservative one.
A dual algorithm computer lets you pick which model it runs, usually a liberal option and a conservative one. It is a genuinely useful feature for a diver who buddies with people on other brands, because it lets you match the group rather than argue about whose computer is right. Set it before the dive, not during it, and do not change it between repetitive dives.
Whichever model a computer runs, the rule is unchanged: your own computer supersedes any published table, two computers on the same dive can legitimately disagree, and a buddy pair runs the dive on the more conservative of the two. The algorithm comparison covers the trade in detail, and the no-decompression limits table shows how far apart published figures can be.
What nitrox mixes can the Pro Plus 4.0 handle, and to what depth?
The Pro Plus 4.0 accepts oxygen fractions up to 100 percent. That covers every recreational mix and the oxygen-rich gases used for decompression in technical diving, so the computer will never be the limiting factor.
Maximum operating depth is set by the oxygen partial pressure, not by the computer. MOD in feet of sea water equals 33 multiplied by the maximum ppO2 divided by the oxygen fraction, minus one. The working maximum is 1.4 ata for the bottom phase of a dive, and 1.6 ata is a contingency ceiling used for decompression gas at rest rather than a target to plan against.
| Mix | MOD at 1.4 ata | MOD at 1.4 ata, metric | MOD at 1.6 ata |
|---|---|---|---|
| Air (21%) | 187 ft | 57 m | 218 ft |
| EAN28 | 132 ft | 40 m | 156 ft |
| EAN32 | 111 ft | 34 m | 132 ft |
| EAN36 | 95 ft | 29 m | 114 ft |
| EAN40 | 82 ft | 25 m | 99 ft |
| EAN50 | 59 ft | 18 m | 73 ft |
| EAN80 | 25 ft | 8 m | 33 ft |
| EAN100 | 13 ft | 4 m | 20 ft |
Run your own mix and your own planned depth through the nitrox MOD calculator, and pair it with the equivalent air depth calculator, which handles the nitrogen half of the same decision. MOD is an oxygen limit and EAD is a nitrogen calculation, and a nitrox dive is only planned when you have both.
Whatever the computer accepts, you analyse every fill yourself with an oxygen analyser , sign for it, and set the mix on the computer before you get in. A computer set to air on a nitrox fill is merely conservative. A computer set to EAN36 on an air fill is dangerous, because it will show you no-stop time you do not have.
Does the display suit the diving you do?
The Pro Plus 4.0 uses a large segment lcd with backlight. Display technology decides legibility more reliably than screen size does, and legibility is the specification that actually matters at depth.
A segment display shows fewer things at once and shows them very large, which is a real advantage rather than a compromise. Big digits are readable through a fogged mask and without reading glasses, and a segment screen sips power, which is why these units run for a year or more on a user replaceable cell. What you give up is the ability to show a graph or to signal a warning with colour.
Whatever the screen, check one thing in the shop before you buy: can you read it at arm's length without your glasses, in dim light, at a glance? Presbyopia arrives for most divers in their forties and it is the single most common reason a computer gets replaced.
How does air integration work on this unit?
Air integration is included on the Pro Plus 4.0, so cylinder pressure and usually a calculated remaining gas time sit on the same screen as depth and no-stop time. The benefit is real and simple: one glance instead of two, and less task loading at the moment when task loading matters. Keep a mechanical submersible pressure gauge in the kit regardless, because a transmitter has a battery and a radio link between it and your wrist, and both can fail.
Air integration does not change how much gas you have or how fast you use it. That is your own respiratory minute volume, and it is worth knowing as a number rather than as a feeling. The SAC rate calculator works it out from one logged dive, and the gas planning calculator turns it into a reserve and a turn pressure.
The Pro Plus 4.0 also carries a freedive mode, which tracks depth and time on breath-hold descents and warns on ascent rate. Useful if you spearfish or freedive on the same trips, and worth knowing that mixing breath-hold diving with scuba on the same day carries its own risks that a mode selector does not address.
Gauge mode turns the computer into a depth and time instrument with no decompression calculation at all. It exists for divers running their own tables or their own plan, and it is not a way to dive past a no-stop limit without the computer complaining. Using it that way is technical diving without the training, and it is the single most common misuse of the mode.
How does it compare with the rest of the Oceanic range?
| Model | Tier | Display | Air integration | Price band |
|---|---|---|---|---|
| Veo 4.0 | Beginner | Large segment LCD | No | $300 to $400 |
| Geo 4.0 | Intermediate | Segment LCD with backlight | No | $400 to $500 |
| Pro Plus X | Expert | Full colour LCD | Included | $1,000 and up |
Staying inside one brand has a genuine advantage that specification tables hide: the menu logic, the app and the transmitter all carry over, and a shop that services one unit usually knows the others. That matters most for air integration, where the transmitter is locked to the ecosystem.
What else should you look at in the same tier?
| Model | Brand | Algorithm | Price band |
|---|---|---|---|
| Eon Core | Suunto | Suunto Fused RGBM 2 | $650 to $800 |
| Aladin H Matrix | Scubapro | $650 to $800 | |
| Descent G2 | Garmin | Bühlmann ZHL-16C with Gradient Factors | $700 to $850 |
| Nepto | Cressi | Cressi RGBM | $700 to $900 |
| Tern TX | Shearwater Research | Bühlmann ZHL-16C with Gradient Factors | $750 to $850 |
| Ocean | Suunto | $750 to $900 |
What should you check before you buy?
- Can you read it? At arm's length, in dim light, without glasses. This is the most common reason a computer is replaced, and no specification captures it.
- Can someone near you teach it? A unit your local shop rents and services is worth more than a slightly better one nobody around you has used.
- Does the battery arrangement suit your travel? A rechargeable unit needs a charger, a cable and a plan on a liveaboard, and it has no hatch to flood.
- Is the price band real for you? This unit starts at $800 or more, and most of what that buys is capability a recreational profile never reaches.
- Are you buying capability or permission? A computer that supports trimix does not qualify you to dive it. Training comes first, always.
Related reading
Frequently asked questions
Does the Oceanic Pro Plus 4.0 support nitrox?
Yes. The Pro Plus 4.0 accepts oxygen fractions up to 100 percent. That covers every recreational nitrox mix and the oxygen-rich decompression gases used in technical diving, so the mix setting will never be the limiting factor on a recreational dive. Remember that the computer accepts a number you type in: you still analyse every fill yourself, verify the actual fraction with an analyser, and set the mix before you dive. On EAN32 at a 1.4 ata working limit the maximum operating depth is 111 feet.
What decompression model does the Oceanic Pro Plus 4.0 use?
The Pro Plus 4.0 runs Dual algorithm, Pelagic DSAT or Pelagic Z+. Pelagic DSAT is at the liberal end of the models in common recreational use, so it will give longer no-stop times than a conservative RGBM implementation on the same profile. That is worth knowing before you dive it alongside a buddy on a different brand. Whatever the model, your own computer supersedes any published table.
Does the Oceanic Pro Plus 4.0 have air integration?
Yes, and a transmitter is included, so cylinder pressure and usually a calculated remaining gas time appear on the same screen as depth and no-stop time. That reduces task loading underwater. You still carry a mechanical submersible pressure gauge as a backup, because a transmitter has a battery and a radio link and both can fail.
What kind of battery does the Oceanic Pro Plus 4.0 use?
Rechargeable. A rechargeable battery means no hatch to flood and no o-ring to maintain, at the cost of needing a charger and a plan on a liveaboard. Charge it fully before travelling and carry the cable, because a proprietary charging clip is not something you can borrow.
How deep is the Oceanic Pro Plus 4.0 rated?
The Pro Plus 4.0 carries a published depth rating of 100 metres, about 328 feet. That is far beyond any recreational limit and reflects technical capability rather than an invitation. A depth rating describes the pressure the housing survives, not a depth you are qualified to dive. The recreational limit is 130 feet, and going past it requires training that this site does not substitute for. Treat the rating as a durability specification.
Is the Oceanic Pro Plus 4.0 a good choice for a new diver?
Probably not. At $850 to $1,000 this is an expert tier unit, and most of what you are paying for is capability a recreational profile never reaches. Travel divers. It is bulky, and a wrist computer plus a small gauge weighs far less. A cheaper computer with a clear display teaches the same habits for a fraction of the money.
How we choose: we compare published manufacturer specifications, published training agency standards, and verified owner reviews across retailers. We do not test gear in person, and every depth rating, cylinder capacity and algorithm name quoted here is the manufacturer's published figure unless we say otherwise, so confirm it on the current spec sheet before you buy. Nothing here is dive instruction, and no calculator output on this site is a dive plan. Scuba diving carries a real risk of decompression sickness, oxygen toxicity, barotrauma and drowning. Dive within the limits of your certification, verify every plan with your own computer, and buy the training before the gear that assumes it.
Logging your own SAC rate and gas plans? The Dive Kit & Air Planning Workbook is the paid version of these pages: 8 printable worksheets you fill in with your own numbers, plus the full PDF, $29.