An extended dive vacation offers exciting opportunities to grow your diving skills

Do upgrade your certifications

Consider working an additional certification into your schedule. Chances are, you’ll be doing the dives needed to get an additional certification, whether it’s Advanced, Divemaster, Underwater Photographer, Underwater Navigator, etc. A complete guide to PADI courses is available at PADI.com.

Do bring a dive skin

Even in tropical waters, you’ll want something to keep you a bit warmer–and to avoid the chafing of your BC straps and other gear, which really becomes an issue when you’ve been diving several days in a row. A t-shirt makes you look like an amateur, and a shorty–well, that’s way more restrictive to your motion than a skin. And, it will be much easier for your buddy and your divemaster to spot you if you’re not wearing the exact same shorty as everyone else on your dive. Dive skins are inexpensive, roll up really small to fit in your luggage, and they dry out pretty quickly.

Do learn the top dive locations ahead of time

Sometimes the coolest dive locations are the ones where the boats only go once a week. Figure out ahead of time the amazing wall you want to dive, the “shark central” dive spot, or the awesome wreck you want to explore, and figure out your diving schedule so that you can make it to each of these.Then, you can fit other more general dives around those dates.

Do bring some of your own gear

While it's a pain to ship and carry around, the “comfort/fit” items like your mask, for instance, will make a big difference after you've been diving a number of days, and when little fit issues, chafing, etc. start driving you crazy.

Do invest a little in an underwater camera

Underwater photography doesn't have to cost a lot. You can get some terrific pictures (and video) without spending a lot of money by using one of the popular point-and-shoot digital cameras. I'm a fan of the Canon Powershot series for this, and Canon makes high-quality housings for many of those cameras for not much money.

Do make a checklist

In exotic destinations, things that are easy to buy back home might not be easily available–and if they are, they might be crazy expensive. If you wear contacts, bring a half dozen spare pairs; bring motion sickness medicine; a mini dry box to hold your keys, credit card, dive card, and tip money; your dive computer; and 2 or 3 swimsuits (putting on a cold, wet swimsuit on day 2 will make your morning coffee not really necessary).

Do not forget your docs

An extended dive vacation typically involves more challenging dives, and a dive shop is less likely to overlook you not having your dive certification card with you in these cases. And don’t forget dive insurance–it’s cheap, and covers things like decompression chamber treatment that regular health insurance might not cover. It’s just $35 to join DAN, and then they have plans ranging from $30 to $75 per year.

Do not wait till you get there to learn to use your new equipment

There’s no better way to make an entire boatful of divers hate you than to delay everyone’s dive because you’re figuring out how to work the knobs on your new underwater camera housing. If nothing else, pack your manuals in your carry-on luggage so you can read up on your new toys on the plane ride.

Do not forget your no-fly times

Although cabins on passenger jets ARE pressurized, it's not really all that close to sea level pressure. Typical pressures are the equivalent of 5000 to 7000 feet above sea level. There’s also good info from the CDC here on diving and flying.

Do not eat/drink too many things with too many histamines

Or you'll have trouble clearing your ears…especially after several days of diving, as your ear passages will get a little irritated. Alcohol: wine, beer, and champagne have the most histamines; food: tuna, mackerel, herring, sardines are high in histamines; avoid fermented/aged meats and cheeses, and pickled vegetables including sauerkraut.

Do not forget a power adapter

Many of the best dive locations in the world are in countries where your rechargers for your phone, camera, etc. won’t plug in without an adapter. Here's a great chart to find what you need by country.