47 Meters Down: Uncaged (2019) on Netflix

Plot summary

Mia has just moved to a school in Yucatan with her stepsister Sasha, and another student, Catherine, pushes her into the campus pool. Mia's father Grant arranges a boat trip so the sisters can watch great white sharks together, and he gives Mia a shark tooth from one of his cave dives. Catherine turns up for the same tour, so Sasha's friends Alexa and Nicole take the sisters to a hidden lagoon instead. The lagoon opens into a sunken Mayan city, where Grant and his assistants Carl and Ben are working ahead of a visit from archaeologists. The girls find scuba gear and swim into the ruins, reaching an old sacrificial chamber. Nicole topples a stone column, setting off collapses, and the stirred silt separates them.