The kids are rollerblading on the streets, and Goldberg all of a sudden has a problem and yells for help, stating "I'm a goalie, not a skater!" This doesn't work, since during the first two movies, he was out and about skating with the other kids very fast all throughout the malls and the streets without problem.
While showing the Ducks touch the ice in memory of Hans, you can see #21 skate by. 21 is Dean Portman's number, though he doesn't show up until after the 2nd period of the game.
Right after Charlie takes off his shoulder pads after the first practice, you can see him taking them off again when the scene changes to Connie looking at the list.
During the game against the Blake Bears you see the first 2 goals scored by the ducks, the score board go form 2-0 to 3-0. Then they score a 3rd goal and the score board goes from 3-0 to 4-0, when only a total of 3 goals were scored.
When Portman gets sent to the penalty box, he performs a striptease, yet when Ken Wu gets sent to the penalty box less than a minute later, Portman is fully dressed, pads and all.
The school's ice rink has banners hanging from all over the ceiling and an American flag hanging almost flush to the wall. The flag is hanging vertically with the stars in the top right hand corner, when in fact the proper position of the stars, whether a flag hangs vertically or horizontally, is in the top left corner.
After the coach yells at the Ducks for playing the varsity, Charlie and Fulton skate off the ice on the back of Fulton's jersey says "Fulton" when it should be "Reed." (In the first movie, he is listed as Reed, in D2 in Team USA Jerseys he is listed as Reed, however in the USA Ducks jerseys, he is listed as Fulton.)
The bill for the dinner the Varsity team left for the Ducks to pay for actually comes out to $957. The bill says $857.
The woman on the board who gives a motion to keep the Ducks is the same woman who recognizes the kids who shop at the Rodeo Drive store.
When Gordon and Charlie spend the day together after Hans passes away, they stop to look at an old high school photo of Bombay. The photo places Gordon in high school (probably his senior year) in 1975. Gordon's infamous penalty shot took place in 1973 when he was only 11 or 12 years old.
When Julie is in the goal singing about how Fulton scored, you can see that her lips are not moving from behind her mask.
At the end of the movie, Dwayne Robertson says, "Hey, look what Bombay did," but his lips don't move.
When Charlie and Fulton are throwing up at the amusement park on their day of skipping school, the security guard tells them to "take it outside," but his mouth does not move.
The sound that is made whenever someone scores a goal sounds more like a siren than a horn.
In the final seconds of the game, the announcer says that Conway has a breakaway, in the next shot, a Warriors player can be seen in front of Conway.
Julie's song says that Fulton has only been able to skate for one year but he had been on the team for a couple years.
(While Charlie said most of the team had been together for 4 years; Guy, Averman, Goldberg, Connie and himself were together sometime before becoming the Ducks. Only about a year or less has passed between each movie meaning Fulton has been on the team about 2 years. They were in 6th grade in the 1st movie and in the 3rd are Freshman.)
When Coach Orion posts the positions and Dwayne asks about the captain, Luis Mendoza's listed as #6, but 6 is Julie Gaffney's number. Mendoza wears #22.
The commentator notes that Charlie doesn't have the captain's C and says that Charlie has been the Ducks captain since the team began, but in the second film, it is specifically said that Adam Banks is the team captain. The team starts as Team USA but changes to the Ducks at the end, so Charlie was not always the captain of the Ducks.
Last period of last game against the varsity team. Too many men penalty is called and coach tells Luis to go take the penalty. When the penalty box is seen, it's still Portman and Ken (not Luis). This isn't correct. If listened to closely, Coach Orion can be heard telling Luis to get back to the Ducks' bench and not take the penalty, and he does indeed tell Kenny to go to the penalty box.