When Norman lets Billy Ray go off in the boat by himself, he speeds across the lake. Billy Ray and the steering wheel are on the alternate sides of the boat in subsequent shots.
When Ethel and Norman first drive to Golden Pond, it's supposed to be early spring, However, there is a close-up of Queen Anne's lace, which is a flower that blooms in late summer.
Pieces of mail change between shots. In particular, there is no printed advertising flyer or newspaper in the first shots, and there is never a padded envelope containing Norman's meds included in the sheaf of envelopes that the postman delivers. Norman pulls out the letter from Chelsea and hands it to Ethel, then he says that there is nothing else besides "bills and junk mail."
There are windows on the landing of the stairway up to the second floor. When Chelsea, Billy, and Billy Jr. arrive, it's dark outside. However, sunshine is coming through the windows on the landing, whereas all other windows are dark. It is verified that it is dark outside when Chelsea comes into the house and greets her father.
When the mailman comes earlier in the movie, the screen door is broken. A few scenes later, when the door is open, it goes back to the closed position. Later on it is broken again.
The numbers of the pump show the cost of fuel to be 67.9 cents per gallon with a total cost of $19.00. The price of gasoline in 1981 was around $1.30 per gallon. However, old pumps were not capable of charging more than 99.9 cents per gallon, so they were set to half the price, and the total was then doubled. That is why the teenager asks for $38.00.
There are a couple of reverse shots during Billy's boat ride on his own that switch him to the opposite side of the boat.
When Ethel and Norman are watching the loons from their boat, there are obvious decoys placed where the loons should be. The decoys aren't even in the correct shape of a loon.
When the boat crashes into the rock, a panel can be seen sliding over to reveal the hole in the boat.
In the final scene of the movie, Ethel is seeing mouthing words but nothing is heard on the soundtrack.
When Charlie and Ethel find Norman and Billy hugging a rock in Purgatory Cove, she dives into the water and swims to them which makes no sense. She's not going to be able to help them and risked her own life for no reason other than for dramatic effect. Charlie could have easily maneuvered his boat over to them and so now he has to pull Ethel out of the water too .
When Billy Ray is circling the sailboat in the lake, the shadow of the helicopter used to film the scene can be seen.
As Ethel and Norman prepare to leave the dock after gassing up the boat, the microphone boom is reflected in the boat's windshield. It moves each time one or the other actor speaks.
The ages of certain characters are portrayed as younger than the actual age of the actors.
Bill Ray mentions that he is 45 but at the time of filming ,Dabney Coleman was 49. Billy says he's 13 when at the time Doug McKeon was around 16. Norman is having his 80th birthday yet Henry Fonda was 76 at the time. Ethel mentions that she is in her 60's yet Katherine Hepburn was 74 at the time.
After they arrive at Golden Pond and Ethel brings firewood into the cabin, she says that Norman is in his seventies and she's in her sixties, but both Henry Fonda (76) and Katharine Hepburn (74) were in their seventies when the film was made.