How to pick a compact night dive torch for lanzarote and test beam spread, battery life and strobe compatibility

Night diving around Lanzarote is a different world. The black volcanic backdrop, bioluminescent plankton patches and sleepy reef life make for unforgettable dives — but only if your torch works for the job. Over the years I’ve tested a fair number of compact night dive torches while guiding and teaching here, and I’ve learned that size alone doesn’t tell you whether a torch will be useful in our Atlantic conditions. In this article I walk you through how I choose a compact night dive torch for Lanzarote and the simple, repeatable tests I run on beam spread, battery life and strobe compatibility.

Why compact torches for Lanzarote?

Compact torches are my go-to when I’m guiding night snorkels, teaching confined-water skills or carrying a backup on drift and shore dives. They’re lighter, fit easily into pockets or BCD pouches, and don’t get in the way when I’m photographing shy critters. But compact doesn’t mean basic — the right one still needs enough output, a useful beam pattern and reliable runtime in cooler Atlantic water.

Key features I look for before buying

• Output (lumens): For close-range work and fin tips, 300–800 lumens is usually enough. For search tasks and wide visibility in choppy water I prefer 800–1200+ lumens, but that’s less “compact”.
• Beam type: Flood, spot or a balance. I favour a well-defined flood for night diving reefs — it lights foreground and background without a sharp, uncomfortable hotspot.
• Battery type: Rechargeable 18650 cells are common and offer great value, but integrated packs or AA-based torches are fine if you travel light or want easy spares.
• Strobe/DSMB compatibility: If you use a surface marker buoy or want to signal in poor visibility, the ability to add a strobe module or have a programmable flash is handy.
• Build quality and seals: Lanzarote’s sand and salt demand good O-rings and corrosion-resistant switches.
• Size and weight: It must be genuinely pocketable when inflated, and comfortable to hold for 30–60 minute night dives.

Testing beam spread — a simple shore test

Beam spread tells you how the light is distributed. A narrow beam is great for signalling and penetrating murky water, but a wider beam is better for scanning a reef when you’re diving slowly and looking for crabs, octopus and nudibranchs.

Here’s the shore-based test I do before I take a new compact torch into the water:

• Choose a dark night and a flat, featureless wall (a quay wall or the side of a closed building works well).
• Stand three distances from the wall: 1m, 3m and 6m. Hold the torch the way you would underwater (two-handed or one-handed).
• Switch through power modes. Observe beam uniformity (are there halos or dark rings?), hot-spot intensity, and the size of the illuminated circle at each distance.
• Take photos with your phone (turn off flash and exposure compensation) to compare beam shapes.

What I look for: at 1–3m the beam should evenly light a decent area without an overwhelming central hotspot that washes out nearby details. At 6m I want a usable, focused centre with a visible, softer flood around it. For night reef work on Lanzarote, an ideal compact torch has a medium-wide flood with a soft transition to the hotspot.

Measuring battery life — an easy stopwatch method

Manufacturers give runtime numbers, but real-life use (mode switching, current draw in cold water) changes everything. I use a repeatable method:

• Fully charge the battery or insert fresh cells.
• Set the torch to the mode I’ll actually use (usually medium or high, not turbo which is unrealistic for longer dives).
• Start a stopwatch when I switch it on and run the light continuously until it steps down, blinks, or drops below the usable threshold for my tasks (I define “usable” as the point where reef detail is no longer clear at 2–3m).
• Record the runtime and the final lumen mode if the torch steps down before failing.

Tip: Do one test in ambient room temperature and one in a bucket of cold water (~15°C) to approximate Atlantic conditions. Cold reduces battery performance; I’ve lost 10–30% runtime depending on chemistry.

Strobe compatibility and signalling tests

Signalling matters in night shore entries, strong currents or when coordinating across groups. Some compact torches offer built-in flash modes; others are compatible with add-on strobes or sync cords. Here’s how I check compatibility:

• Confirm whether the torch has a dedicated strobe mode and whether that mode is accessible while underwater (some need a surface pre-program).
• If using an external strobe module (e.g. SeaLife or aftermarket strobes), attach it with the recommended sync cord and test firing patterns on land first.
• Test visibility across distances on a calm night from a marker buoy or pier: can your group reliably see the strobe from 100m in typical conditions? In choppy or foggy conditions visibility decreases; conservative planning is essential.

My practical rule: if I can’t see the strobe clearly from 50–100m on a dark, calm night, it’s not good enough as my primary surface signal. I carry a dedicated high-output strobe or an SMB with an integrated strobe for that purpose, and use the compact torch for reef work and short-range signalling.

Real dives: how I evaluate a torch underwater

After the shore tests I take the torch on a few predictable night dives around Puerto del Carmen and Los Charcones. I assess:

• Comfort: grip, switch + glove compatibility, heat build-up during long swims.
• Beam behaviour: how it lights foreground and background, colour rendering (important for photography), and how marine life reacts.
• Switch reliability: can I cycle modes confidently while managing my SMB, camera or buddy link?
• Runtime in situ: I time our dive legs and check battery percentage or voltage after 30–50 minutes of use.

I also test the torch against sandy conditions — Lanzarote’s shore dives can produce sand clouds that demand a stable beam and easy-to-clean bezel.

Compact torches I often recommend

Note: the models above are examples to illustrate types; check the latest specs and user reviews for up-to-date performance. I also favour torches with user-replaceable 18650 batteries because they’re easy to source and give consistent performance in cold water.

Checklist before any Lanzarote night dive

• Fully charged spare batteries and a plan for warming spares if nights are cold.
• Tested strobe or surface signal visible at distance.
• Secondary or backup torch (compact but reliable).
• Practice mode switching with gloves before entering water.
• Check O-rings, buttons and carry lanyard or clip.

Choosing a compact night dive torch is a balance between practical size, usable beam and reliable runtime. For my Lanzarote dives I prioritise a soft flood, glove-friendly switches and batteries I can replace or recharge easily while on island trips. If you want, tell me the models you’re choosing between and I’ll help you pick and suggest which tests to run before taking one on a night dive here.