What should I buy first?
Start with an honest question to yourself: how much am I actually going to dive? Did I get certified for one trip and then we'll see — or am I planning to make this a habit? Diving can be a costly hobby. There's a running joke that, like absolute zero at −273 °C, everything in diving seems to start at about $273. The number's a coincidence; the sentiment isn't.
If this was for a trip and you don't yet know what comes next, the answer is easy: rent everything, pee in the wetsuit like everyone does, return it, and be happy. Don't spend a dollar you don't need to until you know you'll keep diving.
But if you're planning to dive regularly, two things shift. First, there's a point where the rental fees add up past the cost of just owning the gear. Second — and this matters more than the money — familiarity with your own gear goes a long way. I personally always travel with my own kit; the only things I rent are weights and tanks. Everything else comes with me. So the real question is what to buy first, and why.
Start here: the mask has to fit
The very first things are mask, fins, and snorkel — and the mask above all, because a mask has to fit. I usually assume you bought one before your Open Water course, but if you haven't: go to your shop and try several. A mask that seals on one face leaks on another; there's no substitute for trying it on yours. Here's my actual advice — find one that works, dive it a couple of times, confirm it really seals and stays comfortable, then go back and buy a second one just like it. A genuinely good-fitting mask is hard to find, so when you find one, don't be caught without a spare. I always carry a backup mask in my pocket when I dive.
One more thing about masks, and it matters more if you have long hair: most come with a plastic strap that loves to tangle hair. I've watched countless divers fight to get a mask off with half their hair knotted into the strap. There are now straps that are a single stretchable band — comfortable, quick, and nothing for hair to catch on. Worth thinking about; ask your shop.
As for the snorkel: we strongly encourage you to have one on every dive, but that doesn't mean it has to dangle off the left side of your mask the whole dive, driving you crazy. A snorkel is a surface tool — it has zero use underwater, and for me a fixed one just gets in the way every time I clear my mask or take it off and put it back on. There are snorkels that roll up into a ball and tuck into a pocket; you pull it out when you actually need it on the surface. Something to consider. As always, this is my preference for the way I dive — talk to your instructor and your shop and do what's right for you.
The first real investment: a dive computer
After that, the most important purchase, for me, is the dive computer, and the reasoning is worth spelling out. A computer does two simple things: it tells you about the dive you're doing now, and it tracks what you've done before now. That second part is the catch when you rent. A computer you rented for dive one on island one doesn't hand its profiles to the different computer you rent on island two — so you lose a major piece of your safety picture: your repetitive-dive history and your surface intervals. Owning one computer that follows you across every dive keeps that record intact.
There's a second reason, just as important. If you're used to a Windows machine and someone hands you a Mac, you feel lost for a while — right? A dive computer is no different. On a boat, mid-trip, is the wrong moment to be reading the manual. A ten-minute walkthrough at the shop won't get you comfortable with all the nuances and alerts either. Diving your own computer, the one you actually know, is worth more than a fancier one you don't.
So how elaborate should it be? Your first one can be basic — but make sure it supports Nitrox. I promise you'll pick up Nitrox sooner or later, and you don't want to outgrow the computer on day one. Call it somewhere around $500. That computer can last you a very long time and may never quit. Later you might want one with air integration and more features — no problem. Your first computer becomes your backup, and you want a backup: I never dive with only one. If one floods or dies at depth, complaining about it down there solves nothing — I need to surface, and then I can complain. The backup is what gets me there.
Exposure protection: the wetsuit
One related note, since it comes up the moment you start thinking about exposure protection: how cold you get underwater isn't really about the water temperature, it's about your heat budget — which is why the right suit for where you dive is a question for your shop, not a chart.
There's a caveat to all this, though, and it's a real one. Do you want to dive in a wetsuit the last renter peed in? Remember, there are two kinds of divers: those who admit they've peed in their wetsuit, and those who've done it but won't admit it. It's not bad manners — it's physiology and pressure. Cold-water immersion shifts blood inward and your body makes urine faster; most divers feel the urge within minutes of getting in. DAN has a good, frank write-up on it here.
Say that doesn't bother you — it's just urine, rinses out. Fine. But there's a second problem rentals can't fix: fit. If you're at either tail of the distribution — XXXX-Small or XXXX-Large — you'll struggle to find a rental that actually fits, and a wetsuit that doesn't fit isn't just uncomfortable. It wrecks your buoyancy. A loose suit traps pockets of air that shift around as you move, and holding neutral becomes a constant fight.
That's the case for buying your wetsuit first — fit matters that much. And by fit I don't mean how it looks; I mean whether it does its job. A wetsuit keeps you warm by holding a thin layer of water against your skin: that water warms to your body temperature and you sit a little above ambient. If the suit is loose, that water flushes through and never warms up — so the suit keeps you warm in name only. A suit that fits is the difference between insulation and decoration.
One preference, when you do buy: the wetsuits you see in movies are one-piece, but I far prefer a separate top and bottom (a "two-piece" or farmer-john setup). It makes the surface interval so much easier — you can drop the zipper or peel the top off and sit in just the bottoms between dives, instead of being sealed head-to-toe in the sun. It also makes the bathroom run survivable: picture coming out of the water, hurrying to the head, and then fighting to find a zipper pull somewhere behind your shoulder blades — blah, blah, blah. That's not a hypothetical; it's years of experience talking.
On top of the suit I always wear a pair of technical shorts with two pockets — these go on over your wetsuit bottoms and give you somewhere to actually put things. In one pocket I keep my spare mask; in the other, my wetnotes and a small stainless-steel multi-tool for hoses and valves. That little tool has saved more trips than I can count — the difference between a quick fix on the boat and a dive you sit out. Right beside it I keep a stainless marine adjustable wrench — the kind built for saltwater that won't seize up on you. Sea-Dog makes a good one; look it up and pick it up locally if you can.
In the same spirit, pack a save-a-dive kit. It's a small, cheap pouch of the little things that otherwise end your day: an assortment of O-rings in common sizes, a spare mask strap and fin strap, a mouthpiece and zip ties, maybe some silicone grease and a few spare buckles. None of it costs much, and all of it fits in a corner of your gear bag — but the day a tank O-ring blows a steady stream of bubbles at the dock, a ten-cent ring is the only thing standing between you and watching everyone else descend without you. This is the cheapest insurance in diving. Your shop can put a good starter kit together for you, and you'll slowly learn which extras are worth adding for the way you dive.
Skip these for now: BCD, regulator, tank
Now, what about the big-ticket items — BCD, regulator, tank? You'll see people buy all three right after Open Water, and I really don't recommend it, at least not early. They're the expensive end of the sport, and if you're not diving often there's simply no reason to own them. Worse, they cost you whether you use them or not, because they need maintenance on a schedule, not on usage. A regulator wants servicing every year or two regardless. A tank needs an annual visual inspection and a periodic hydrostatic test regardless. Buy these, dive twice a year, and all you've really bought is a standing service bill. Rent them until you're diving enough that ownership actually pays off.
Next: a rash guard
So what should come next, once you've got a computer and a suit that fits? Top of my list is a rash guard — and the reasons go beyond what people expect. In a warm, tropical spot you can often dive in the rash guard alone, no wetsuit at all. It protects you from scrapes, from the sun on the surface, and from whatever the environment brushes you against. But here's the part nobody mentions until you've felt it: a rash guard makes putting on a wetsuit so much easier. The suit slips right on over it, instead of you fighting to drag neoprene up a bare, half-dry body. Try it once and you'll never go back.
Once you're diving the ocean: SMB and a cutting tool
Say you're now travel-ready — computer bought, wetsuit rented, rash guard packed. Now what? Once you're diving in the ocean, two more items stop being optional for me.
The first is a surface marker buoy (SMB). When I dive the ocean I never go without one — it's one of the most important safety items there is. We advocate carrying at least three signaling devices, and the SMB anchors that count: most BCDs come with a whistle attached (there's one), the SMB itself is mandatory in the ocean as far as I'm concerned (two), and many SMBs have a small pocket that holds a signaling mirror and a tiny flashing light (three and four) — and that flashing light can save you if you ever find yourself without a dive light on you. Check with your dive shop first, but you may also want to look at DAN's safety gear. An SMB is what makes you visible to the boat when you surface away from it, and what marks your position on a drifting ascent. Buy one as standard kit — the cost is far less than renting it dive after dive.
The second is a cutting tool. Never dive the ocean without one. I deliberately don't call it a "dive knife" — we're not using it for anything the word knife implies. It's there to cut you free if you're tangled in fishing line, netting, or anything else that traps you. I carry three of them, and you can call me paranoid for it: one on my left, one on my right, and one under my dive computer. The logic is simple — if I'm entangled, I need to be able to reach a cutter with either hand, because the one time I need it is exactly the time the other hand might be the only one free. As with the SMB, buying beats renting by the second or third trip.
As always: check with your local shop first — they know what works in your water.