Seek training in advance

If you are not diving with an experienced diver it is important to seek professional training from a certified instructor for your first night dive.  Most advanced diver courses include night diving training or if you are in a rush check with your local dive shop and see if they offer training specifically for night diving.  PADI offers a specialty course for night diving that teaches the standard procedures used by night divers that are important for your safety and convenience.

Share your dive plan

Be sure that you tell someone of your dive plans, including where you will be diving, who will be with you, what time you expect to be back, when you expect that you will check in once the dive is finished and emergency phone numbers for the local rescue authorities.  This may seem extreme but just like going on a hike it is always best to be sure that others know your plans so if there is an emergency they will know where to start looking for you.

Know the law for where you are diving

Some parks and beaches close after sunset and local fishing laws may change at night so check with a local dive shop or bait store before you dive at night.  Also, be aware of the parking restrictions in the neighborhood.  The worst thing is to return from a great dive and find an expensive ticket on your vehicle or worse yet that your vehicle has been towed.

Don't be late

Plan ahead where you are going to be diving and arrive prior to sunset to give yourself plenty of time to unload and assemble your gear, familiarize yourself with the surroundings, and check your dive site information while there is still enough light.

Start your dive at twilight

One of the most exciting and enjoyable times to start a night dive is at twilight.  During this time you'll experience the dive site making its transition from the day shift to the night shift.  It is like the parents going home and the college students coming out to party.

Know the area

Your night dive should be in an area you or your dive buddy is familiar with from one or more day dives.  If it's the first time you are going to dive the site be sure to arrive earlier in the day and do an exploratory dive so you are familiar with any hidden obstacles.  Be sure you know how to navigate the dive site and how to get back to the boat or the shore. area.

Know your signals

Diving at night requires that you use light signals as well as hand signals.  When signaling with your light aim it toward the seabed where your buddy is looking not in their face.  The following are common light signals.

• A slow large circle means "OK".  It is the same as the finger and thumb circle.
• Rapid side-to-side movement underwater means "Attention, look this way."
• Rapid side-to-side movement on the surface means "Problems come get me."
• When you need to use hand signals, shine your light on your hand so your buddy can see it.  If you need both hands then tuck your light under your arm.

Since it is easy to misunderstand signals in the dark it is important that your buddy confirm your signal by repeating it.

Bring a lighted signal device

Bring several glow sticks to mark your entry site when shore diving. Locate a fixture that you can attach a glow stick to provide a fixed location for your return to the beach.  Make sure each diver attaches a safety light or glow stick either to their tank or snorkel so they can be tracked.

Bring a light and a backup light

Make sure each diver has their own primary light and always bring a backup light encase your primary light fails.  You only have to h ave your light go out once without a backup light to learn this lesson.

Once you reach the bottom, turn off your light to see how much ambient light there is.  This will also give your eyes a minute to adjust and yo will be surprised, with your light off, how many more fish and marine life you will see.

If you do need light, you'll want to use the edge of the pool of light to pick out the marine life.  This will help to keep them from disappearing and provide you with an enjoyable dive.  Remember to use a minimal amount of light.

Don't forget to check your batteries and pack extra ones.  It is always best to place new batteries in your lights or any equipment that you are using to avoid problems.

Be sure that you secure your light to your wrist with a strap, they're inexpensive and it will keep you from dropping and losing your primary it. Your dive light will drop and dangle from your wrist when you let go of them, so if you need to free up a hand, turn the light off prior to dropping your light.  This will ensure that you don't blind your dive buddy or send any confusing signals.

Remember what to do if you become separated

If you become separated from your dive buddy, get to the surface safely and shine your light outward while slowly turning in a full circle and looking for your buddy's light.  If you're diving from a boat, surface and point your light at the boat until you get their attention, then shine it down on your head.  You do not want to effect their night vision since it well take them a good 15 minutes for their eyes to adjust and they may not be able to see you very well during this time.

Bring snacks and drinks

Make sure you bring snacks and drinks for after your dive.  You will want to rehydrate yourself and you will have burnt a lot of energy so having high energy snacks like energy bars or fruit will help .  Be sure that you drink plenty of water and stay away from soft drinks or alcoholic drinks since they will only dehydrate you more.

Bring a dry bag

Be sure to pack a towel, dry cloths and sweater in a dry bag to change into after your dive.  You will want to be sure that it is placed in an area above the high water mark if you are shore diving or is left in your vehicle.  Depending on the season you may want to also bring a small blanket to keep warm.