You do it like the barrel role flip, first you do the barrel roll(you only need to bo going around 100) after you complete it let your craft come = to the water then move the joystick to the same side as you have it held to diaganally down. (left, then right wait to come = with the water then do diaganaly right) as your craft hits the water you'll kinda do a cork screw. It's worth about 3400 points.
This is a Barrel roll Flip to do in the stunt mode:
Get all the way up to the fastest speed you can. I'm usually up to 118. Approach the ramp the same way you would if you were doing a barrel role. (To do this trick, you must have already mastered the barrel roll) On the ramp, move the stick left, and then in the air move it to the right, like a regular barrel roll, but when you move it right, rotate the stick backwards so you a flip. Let go as soon as the bottom of the jetski is parallel to the water. This can also work for a barrel roll from right to left. Again, move the stick to the left, to the right, and then back-right. You should get at least 1500 points. I've gotten 2000 points at Dolphin Park off the first ramp you get to. Hope this helps!
Inverted Helicopter Flip:
While on the ramp, tap diagonal down-right and hold diagonal Up-left to do an Inverted Helicopter Flip.
Get up Fast
After you have fallen off your jetski then press the A button very quickly until the guy is up on it, if you do this you will get up faster than normal.
Ride the dolphin
Select Stunt Mode, Select Dolphin Park,
You will need to: Collect all of the rings, Handstand, Stand and Somersalt, Ride Backwards, Flip off ramp, Clockwise and counterclockwise barrel roll off ramp, Submarine off ramp.
When you cross the finish line you will hear dolphin noises.
Select Championship mode normal, Enter Warm-up mode, Hold down while selecting your racer, then press A.
You will then ride the dolphin, It can flip, Barrel roll, and submarine.
Stunts
Double flip stunt:
First get some speed with the jet ski. When you are on the ramp tap up one inch from the top of the ramp and hold down to do a flip. Instead of making the character do one flip hold the down button longer so he does another turn. If you do it correctly he will land perfectly and ride on. J. Meter is the best guy to do this especially on small ramps. You get 2000+ points for this stunt. I have gotten 3120 for this stunt in Sunny Beach because the "judges" (the algorithm which calulates the score) gives you more for a smaller ramp and the height you jump off the ramp.
Helicopter Stunt:
It is a variation of the flip where you spin sideways. When you are on the ramp turn sharply diagonal left-up or diagonal right-up then hold down to do a sideways flip. You can get an average of 1700+ points for this.
Helicopter into a flip stunt:
Do the helicopter stunt as listed above but hold the button down longer. It will look like he does a helicopter move but then rotates so he is in the upright position and does another flip. You can get 2500+ points if done correctly. I have gottn 3450 points on the first ramp in Twilight City for this.
Triple Flip:
To my knowledge this stunt can only be done at Glacier Park on the big ramp. You need a lot of speed and air to do this. it can only be done with J. Meter on this stage to my knowledge. You tap up 1-2 inches from the top of the ramp and start doing the flip and hold down. you need alot of speed for this one so do not try to do any turns or get hit by the ice block in the water which may slow you down or stop you completely. You can get 3000+ points for this. I have gotten 5610 points because i sort of started like a helicopter stunt with two flips after. Note that this is a difficult stunt to perform and you do need alot of speed, timing, and maybe some tinkering with the costomization of the racer at the character select screen.
Change Racers Colors
Color Change Here's a simple code that'll bring a little difference into the way your characters look. Go to the character select screen, and before choosing characters, push the analog stick or D-pad up and hold it there -- the characters's outfits and jetski bikes will change in color. The number on the jetski will also change.
This is acually the alternate chosen by the computer in Two-player mode. To make the change hold the stick up and then press A or B to select your character.
Speed Bursts
Try to press and hold down the gas button right before the announcer says, "Go!" If you are successful, you will immediatly increse your top speed. It can be incresed anywhere from one arrow to maximum power if you get it right.
Get Mega Points Easily
To rack up MEGA points in Wave Race 64 stunt courses, press the pause button as soon as you complete a stunt. If you do it right, all sounds should stop except for the announcer ("I can do that!", "What a great stunt!", etc.) Usually if you press the pause at the exact moment you hit the water you should be OK, but the idea is to pause it the instant the announcer starts talking (that way this cheat works with handstands, etc.). If you do it right you should get tons of points for the simplest things! You can get 20000+ on Dolphin Park and 30000+ on Glacier Coast!