Goofs

(at around 1h 15 mins) Sam's shirt changes from one camera angle to the next when she and her brother Chris are being hidden in the closet by their mother.

(at around 44 mins) Earlier in the movie, the young boy has to be on tiptoes to push the attic door closed. Later in the movie (at around 1h 19 mins), he can use the same rod to open the attic door.

During the pool struggle scene, cuts to the boy shows his arms around someone's head - you can see the top of someone's head near his shoulder - maybe his sister (who's still in the pool).

(at around 20 mins) When visiting the river where the Alvarez boys drowned, the station wagon plays a sound for the door being open that wasn't available on cars until the middle to late 1980s. Cars in the 1970s would have had a buzzer, not an electronic "ding dong."

Samantha's blanket doesn't match the period. The film takes place in the 1970s. Her blanket in the back of the car while at the crime scene is from Target's Cloud Island collection, which could be purchased in 2018.

The last person on this subject talked about the pool. The time stamps were at 1:12:20 & 1:12:59. Looking at these several times & it didn't make sense. Chris was clearly comforting Sam in these scenes, but you can see Sam's hair, at the same time she's in the pool. Also, right at the beginning of this pool scene, Chris was right next to Raphael, then when Raphael blesses the pool with holy water, Chris is nowhere near him & cuts to those scenes mentioned above.

(at around 1h 25 mins) Anna's car has a seven-digit California license plate in the 1AAA111 format. The movie is set in 1973, but this format was not used until 1980. Cars in California in 1973 had six-digit plates in the 111AAA format.

The movie is set in 1973 when the fashion for men was to have long hair and sideburns. None of the male characters have sideburns, and Sean Patrick Thomas has a fade haircut which wouldn't become fashionable until 20 years later.

(at around 3 mins) Toward the beginning of the film, when Anna types data into a Child Protective Services form, one of the items is a phone number with a 310 area code. This is supposed to be 1973, but the 310 area code wasn't introduced until 1991.

(at around 1h 8 mins) Raphael is shown placing the fire tree seeds (to keep La Llorona out of the house) along the front door and one window, but apparently, he stops there because the back door has no protection. As soon as La Llorona realizes she cannot cross the front threshold, the family panics, realizing she can get in through the back.

(at around 28 mins) Despite the fact she comes in the dark and at night, La Llorona reveals herself at the pool outside in the daytime to the daughter.

There is no reason Anna needs to be called to the river in the middle of the night when the Alvarez boys are found dead. She's a social worker, not a forensic pathologist. Anything she could do for the boys could be done in the morning. If she is called to deal with their mother, that would be reasonable, but their mother is a suspect and is arrested the moment Anna arrives.

(at around 1h 23 mins) When La Llorona grabs people's arms, their arms develop burn marks. But when she grabs Chris' face, nothing happens.