Hahei is a small settlement in Mercury Bay on the eastern side of the Coromandel Peninsula in New Zealand. It is near Cathedral Cove, between the settlements of Cooks Beach and Hot Water Beach. It is approximately 11 km south east of Whitianga and 8 km north of Hot Water Beach.

The driving route to Whitianga from Hahei is circuitous and takes approximately 30 minutes. An alternative route is by road to Ferry Landing, which takes 15 minutes, and then a short passenger ferry trip to Whitianga. A ferry service to Whitianga has served the eastern Mercury Bay area since 1895.

Hahei is a popular holiday destination, with a white sandy beach and sheltered aspect, resulting in safe sheltered swimming waters. Its resident population is around 300, but in peak holiday periods the population swells to more than 10 times this. On the southern end of the beach is Te Pare Historic Reserve, which was once the site of two Māori pā, Hereheretaura Pā and Hahei Pā.

Hahei is located close to the start of the Cathedral Cove walkway and in the peak has nearly 500,000 day trippers and visitors who come just to visit the Cove. This can lead to congestion and parking issues.