Which Dive Computer Fits Your Diving? 3 Advanced Options

Choosing a dive computer becomes much more interesting once you move beyond basic recreational diving. Multiple gases, decompression planning, sidemount, wireless tank pressure and navigation can all become part of the decision — but different computers approach those features in different ways.

The Halcyon Symbios BLUE, Shearwater Peregrine TX and Suunto Nautic are three advanced dive computers that are worth putting side by side. They share some important capabilities, but they are not identical in how they handle decompression, gas management, displays, connectivity or diving modes.

So rather than asking which one is "best", this guide looks at what each computer actually offers and which features may matter most for different types of diving.

The Halcyon Symbios BLUE is designed as a dedicated dive computer for divers who want advanced functionality without moving immediately into the top end of the Symbios range.

Its core decompression system uses the Bühlmann ZH-L16C model with gradient factors, and the computer supports up to five open-circuit gases as well as fixed-setpoint CCR and sidemount modes. It is rated to 120 metres and uses a 2.4-inch transflective full-colour display.

That combination makes the BLUE particularly interesting for divers whose equipment requirements may change as their diving develops.

The Symbios BLUE also has a relatively compact, tactile interface. Its two-button operation is designed to be straightforward to use while diving, including when wearing thicker gloves. Mike's lists the handset at £630 at the time of writing, with a separate Tank Pod bundle also available.

That makes the BLUE worth considering for divers who want advanced open-circuit capability alongside fixed-setpoint CCR functionality, while keeping the option of adding compatible accessories later.

The Suunto Nautic takes another route.

It combines advanced dive functions with a large 3.26-inch AMOLED display, built-in GPS, offline maps and a wider collection of navigation and outdoor features. Suunto rates it to 200 metres and specifies support for up to five gases, sidemount, helium and decompression planning.

The display is one of the most immediately noticeable differences between these computers.

The Nautic uses a 3.26-inch AMOLED screen with 720 × 382 resolution. The Symbios BLUE uses a smaller 2.4-inch transflective colour display, while the Peregrine TX has a 2.2-inch full-colour LCD.

These are different display technologies rather than simply three different screen sizes.

For a diver who prioritises a large, modern display and surface navigation features, the Nautic's approach may be particularly appealing. For someone who prefers a compact dedicated dive computer with a transflective display and tactile buttons, the Symbios BLUE takes a different approach.

The Nautic's CCR functionality goes further than a single setpoint. It handles diluent and bailout gases within an eight-gas ceiling, offers both automatic and manual setpoint switching with setpoint alarms, and adds a dedicated CCR switch window alongside a bailout TTS item. CCR data also carries through into the dive summary. For divers starting a dive on a hypoxic mix, it supports Trimix below 18% as the active gas in both CCR and Multigas modes.

Decompression is one area where comparing specifications requires a little more context.

The Symbios BLUE and Peregrine TX use Bühlmann ZH-L16C with gradient factors. The Suunto Nautic uses Suunto Bühlmann 16 GF and allows adjustment of low and high gradient factors.

The important point is that these aren't simply interchangeable labels.

Different manufacturers implement their algorithms and user controls differently, and divers may have preferences based on their training, diving configuration and existing equipment.

If you are using a computer for decompression diving, make sure you understand the algorithm, conservatism settings and planning tools before relying on it for a particular dive profile.

A computer is also not a substitute for appropriate training, planning, gas management or conservative decision-making.

All three computers can be used with multiple gases, but there are differences in how many gases they support and how wireless tank pressure is handled.

The Symbios BLUE supports up to five open-circuit gases and can be paired with Symbios Tank Pods. The Peregrine TX supports three gases and uses Shearwater transmitters for wireless air integration. The Nautic supports up to five gases and uses Suunto Tank Pods.

When comparing air-integrated computers, remember to include the transmitter in your budget.

The computer itself is only part of the system.

If you already own a compatible transmitter from the same ecosystem, that may also influence which setup makes the most sense.

Sidemount divers have good reason to look at all three.

The Symbios BLUE has a dedicated sidemount mode, the Peregrine TX offers full sidemount support, and the Nautic supports sidemount configurations with wireless tank-pressure monitoring.

However, the details matter.

Consider:

• How many cylinders you normally monitor

• Whether you want wireless tank pressure

• How you want gas switching displayed

• Which transmitter system you already use

• How the computer sits on your arm alongside your sidemount equipment

For someone building a complete sidemount system, it is worth looking at the computer, transmitters and other equipment as one setup rather than choosing the computer in isolation.

Battery figures can look very different between these computers.

The Symbios BLUE is rated for approximately 30 hours of diving, while Shearwater quotes up to 30 hours for the Peregrine TX at medium brightness. Suunto quotes substantially longer battery performance for the Nautic, with its current specifications listing 80–190 hours of dive battery life depending on usage.

Actual battery performance will depend on settings, display brightness, dive profile and other factors.

For regular divers, it is also worth thinking about your charging routine. A shorter quoted runtime isn't necessarily inconvenient if you regularly charge your computer, while a longer runtime may be particularly useful for liveaboards, extended trips or divers who simply prefer fewer charging sessions.

The choice ultimately comes down to which features you will actually use. A diver who never uses GPS has little reason to prioritise it, while someone progressing towards fixed-setpoint CCR may consider that capability important.