Blooper

(at around 1h 21 mins) At the climax of the movie, during the ceremony to contain 'The Curse', Rose is asked to drink from a cup. She picks it up from it's place next to the ceremonial candles and does so, when she does, her body convulses and she drops the cup. It rolls across the floor, but moments later she is seen laying on the floor next to the ceremonial candles, with the cup sitting neatly in it's place, upright and next to the candles.

Max grabs Naoko by her hair in one shot when he's about to stab her. In the next shot however, he's grabbing her by the chin.

(at around 51 mins) As Naoko and Lisa are speaking in the park (right after Rose goes off to the swings), Naoko tucks her hair behind her left ear. In the next shot, her hair is back in front of her ear.

(at around 19 mins) In the bathroom scene as Brenda is getting ready to take her bath, one shot shows the tub only half full but in the very next shot, it shows the tub overflowing.

Actor Takatsuna Mukai has his name misspelled in the credits as "Takatsuma Mukai".

(at around 4 mins) At the beginning when Jake is being attacked by Kayako, and is grabbed by his arms, both of the hands grabbing him are right sided hands.

(at around 8 mins) When Naoko first enters her office building, she is seen coming out of an elevator. But when she enters her office, a car can be seen passing by the window.

A small line of human skin can be seen above the white makeup on Naoko's face under her hairline and around her ears, revealing the use of white makeup.

When Dr. Sullivan and the Orderly find Jake's mangled corpse, his eyes are very obviously fake.

The grudge curse was created when Takeo murdered both his wife, Kayako, and son, Toshio. Naoko tries to end the curse by getting Rose to drink Kayako's blood during the ceremony she held in the apartment where the curse was reborn. Drinking Kayako's blood would unlikely stop Toshio's ghost, meaning only Kayako would be stopped. This would mean that the curse would not have been ended by Naoko's ceremony.

Kayako's diary, as shown in the previous two films, was a paperback. However, the diary that Naoko possesses, which is supposed to be Kayako's diary, is a hardcover book.

(at around 57 mins) Naoko is incorrectly referred to as Naoko Saeki on her phone message. Although she is Kayako's sister, Kayako's married name is Saeki so Naoko's last name should be Kayako's maiden name of Kawamata.

Though Max is under the influence of the curse in that scene, him brushing off Gretchen's death as simply her being "old" is ridiculous. Not only did she very obviously die an unnatural death, having her eyes gouged out and jaw ripped off, but she doesn't look old enough to be elderly (actress Marina Sirtis was only 53 during filming).

Toshio is deathly and unnaturally white throughout the film as a ghost, yet Lisa does not seem to acknowledge this when she first sees him, mistaking him for a human boy even.