Halcyon

Halcyon Symbios HUD

A mask-mounted, full-color heads-up display built for team and CCR diving.

Open BLE sync (libdivecomputer)

Syncs wirelessly with third-party apps (Subsurface, Currents, etc.), not just the manufacturer app.

Halcyon Symbios HUD
4.2Comparison Score
$1350
Released2025
Max depth rating120m
AlgorithmZHL-16C with adjustable gradient factors
Air integrationwireless
Wirelessbluetooth
DisplayTFT full-color micro-display, 320x240, virtual image ~20x20cm at ~70cm
Batteryrechargeable
Digital compassYes
Gas typesair, nitrox, trimix
Gas switches5
CCR capableYes

"Gas switches" is how many different mixes this computer can be programmed to switch between mid-dive, mostly relevant for technical/staged-decompression diving. It doesn't tell you which gas types (air, nitrox, trimix) are supported. See Gas types and the product description above for that.

Pros
  • Full-color mask-mounted display keeps critical data in view without breaking eye contact with your team
  • Up to 5 gases for open circuit, fixed or integrated CCR, and integrated sidemount
  • Buddy-screen mode for sharing key data with a dive partner
Cons
  • Niche mask-mount form factor
  • Up to 12 hours of runtime per charge, shorter than the Symbios Handset
  • Best suited to team/technical diving, overkill for casual recreational dives
Diver community sentiment
Mixed opinions

Divers on Scubaboard generally like the Symbios HUD's low-profile, lightweight mount and its glanceable readability, calling it one of the less intrusive HUDs available; one blogger also praised build quality, screen brightness, and battery life hitting the claimed ~30-hour runtime. Recurring complaints center on software polish: a real-world user found the on-screen layout cramped and called the companion app "pretty poorly designed," reporting laggy depth updates during mid-water deco stops. Other threads flag the HUD as a common troubleshooting/failure point in rebreather forums and note the non-replaceable battery and buttons that are hard to operate in thick drygloves.

Scubaboard: real-world app/display complaintsScubaboard: positive HUD usability feedbackMarius Svanevik: independent hands-on review

Summarized from public forum discussion (Scubaboard, Reddit, and similar), not a survey we ran ourselves. See the linked threads for the original conversations.

The Symbios HUD is Halcyon’s mask-mounted display in its modular Symbios computer ecosystem, aimed at technical and CCR divers who want dive, team, and gas data projected in their field of view rather than on a wrist unit.