Continuity mistake: When Data activates his 'slick shoes' on the log bridge, the heels of the shoes pop open to reveal the 'slick shoes' mechanism which starts spraying oil. In the next shot though, they show Data walking across the log, the heels of the shoes are closed, and the oil squirts out of holes in the back of the heels apparently.
Continuity mistake: All the Goonies get soaked while in the Old Moss Garden wishing well, but when they are seen again in another part of the cave they are all dry, and there is not a sign of being soaked.
Continuity mistake: Right after Troy is humiliated at the wishing well, the movie cuts to a television food program, with Sloth's reflection visible in it. The problem is that Sloth's face is noticeably different in this reflection than the rest of the film. For instance, his left eye is only a bit lower than his right eye now, instead of it being considerably lower like it usually is.
Continuity mistake: When Mikey takes the skull necklace off Chester Copperpot, he accidentally pulls Chester's skull off his body. When Mikey does this, the skull is still touching the body, just detached and at the wrong angle. But the next shot we see with the skull, when Brand goes to place the skull back on the body, the skull is about a foot away from the body.
Continuity mistake: During the high speed police pursuit behind the Fratellis, once the second police cruiser pulls behind the first, the squad cars' positions change - in some shots the second police cruiser leads and in some shots the first, just note the different bumpers. (00:02:30)
Continuity mistake: The design on the face of the treasure map and its two holes change, from the scene where the Goonies are in the attic to when they are downstairs again (i.e. it has a red stripe across it at first sight that disappears). (00:16:35 - 00:22:25)
Continuity mistake: In the shot of the Goonies running to the attic upstairs, you can plainly see that it is not raining or stormy outside. When they enter the attic (barely seconds later), it's already raining outside along with the thunder and lightning. (00:13:40)
Continuity mistake: At the Astoria Country Club, when the first shower handle disappears into the wall, the three surrounding tiles break off entirely from the wall. After the next few handles disappear, the wall with the first disappearing handle is shown, but now the square tiles are intact and only cracked.
Continuity mistake: When Chunk and Rosalita are eyeballing each other regarding the statue, there are colored curtains and sheer white curtains hanging from white rods on the two windows behind Chunk (behind the recliner). When Mikey unrolls the map in his kitchen, through the doorway we see that the sheer curtains are gone and now there are shades behind the colored curtains. (00:12:30 - 00:22:25)
Continuity mistake: During the jail escape, when Jake is trying to open the locked door, there is a close-up of Mama Fratelli shouting, "Jake, up!" and we see a police cruiser parked on her left. When they leave, in the overhead shot that space is empty, but next shot a vehicle is there, though it isn't a police cruiser. (00:01:55)
Continuity mistake: When the first police car makes a U-turn, to chase the Fratellis, the squad car's front passenger window is rolled up, as the officer's hands are on the steering wheel. But in the next interior shot, facing that window, it's rolled down - there's even a black wire hanging over the bottom of the open window, to the left. (00:02:30)
Continuity mistake: When Mouth goes down the hole in the fireplace passageway, the cooler base is right beside the fireplace, but when Mikey pushes Data and his backpack into the hole, the base is farther away. When Brand pulls the log holder over the hole the base is back, right beside him, but when Chunk heads for the basement window the base is farther away again. (00:45:45 - 00:47:20)