This is my second year participating in the Dragon Boat Race held on Tuen Ng Festival. I am no expert, but I have gathered a paddlers' shopping list through experience and advice from fellow paddlers, which I hope would be useful for you as well.
Visor
It will be hot out there, but you still need a hat to shield your eyes from rain and seawater. Orca's visor, available from Trisports, will do the trick nicely.
Sunglasses
There is none other than Oakley for a pair of top quality sunglasses, which has lenses that suits both sun and rain. You will need it even if there is no sun, because its main purpose is to act as a pair of (cool-looking) goggles rather than shades. Go to Gigasports to find one that works best for you.
Top
You will definitely want a moist-wicking sleeveless top for your practices. 2XU's singlet is fast-drying, so you won't be weighted down by your top soaking up all the sea water. It can be purchased from Escapade Sports.
Swimwear
Wearing a swimsuit underneath is way better than an actual underwear, which will be soggy within your first few minutes on board. Check out Sabina Swims for their new collection. Since their tops and bottoms can be sold separately, so you can easily mix and match to suit your taste.
Shorts
You should protect your gluts by getting padded shorts from Typhoon8, otherwise you will regret it the day after training. Their products are designed by paddlers for paddlers, so you can be sure that it is well suited ergonomically.
Gloves
There are paddling specific gloves, but I find biking gloves, with thicker padding, works best for me. Get a pair of Giant biking gloves from Bicycle World.
Bandages and Braces
Everyone has different needs, and if you like tape better than gloves, try Mueller's sports tape, which does not peel off when getting drenched. Some paddlers like to put a knee brace on to protect their knee from rubbing and banging against the side of the boat. Again another personal choice, and both items are available from Sportsline.
Sitting Mat
This was considered a must-have by my first dragon boat coach to prevent you from sliding off your seat. It is a cheap investment that you can find in any home ware store such as Japan Home.
Shoes
For a firm grip of the boat while you rotate, you are better off with a pair of Vibram Five Fingers than Havaianas flip-flops. You can try them on at Escapade Sports.
If you find Vibram Five Fingers' design a bit quirky for your taste, you can opt for North Face's Hydroshock series, which are also fabricated with water sports in mind.
Towel
You don't want to look like you are carrying a huge luggage with you every time you practice. With Aquis towels, they are light and fast-drying, making it appropriate to be used at beaches.
Wet Bag
Just because you like paddling doesn't mean you like getting your Smartphone wet. In RC Outfitters, you can find Sea to Summit dry packs available in all shape and sizes.
Sunscreen
Sunburn is no fun, so get Ultrasun's sports formula for a clear, non-greasy sunscreen. Available from 10K Shop.