Tidal Wave (Korean: 해운대; RR: Haeundae) is a 2009 South Korean disaster film directed by Yoon Je-kyoon and starring Sol Kyung-gu, Ha Ji-won, Park Joong-hoon and Uhm Jung-hwa. Billed as South Korea's first disaster film,^[1] the film released theatrically on 22 July 2009 and received more than 11 million admissions nationwide.^[2]

Man-sik, a local from the Haeundae District of Busan, unexpectedly loses Yeon-hee's father while based on a deep-sea fishing boat in the Indian Ocean during the 2004 tsunami, due to an error in judgement. Because of this, he avoids getting involved with Yeon-hee, who runs an unlicensed seafood restaurant, despite her attempts to start a relationship.

Dong-choon and Seung-hyun's grandmother team up with Seung-hyun and get involved in illegal activity to earn money, but are caught by police. Man-sik finally plans to propose to Yeon-hee.

Geologist Kim Hwi runs into his ex-wife Yoo-jin. She has a daughter named Ji-min and a new boyfriend Hae-chan but she and her ex do not tell their daughter that Hwi is her birth father as they are worried about how she might react.

A wealthy college student from Seoul, Hee-mi, accidentally falls into the sea from a yacht. Hyeong-sik, Man-sik's younger brother, is a lifeguard who rescues Hee-mi. Hee-mi is angered by the "violent" rescue and annoys him by following him around, and the two begin to fall in love.

During the fireworks, Man-sik proposes to Yeon-hee. Yeon-hee says a ribbon hung outside her restaurant the day after means yes. On the day after, Man-sik sees no ribbon and meets Dong-choon, who was nearby. Dong-choon tells Man-sik that he told Yeon-hee why her father died several years ago. Man-sik grows furious, thinking that what Dong-choon told Yeon-hee caused her to snub hanging the ribbon and attacks him. During the fight, they see a flock of birds flying away.

Hwi notices that the Sea of Japan (known as the East Sea in Korea) is displaying similar activity to what was observed in the Indian Ocean five years prior. Despite his warnings, the Disaster Prevention Agency assures him that South Korea is at no risk, but a large megatsunami forms because of a landslide near Japan and starts to travel towards Busan, where millions of beachgoers are vacationing. Hwi realizes that Busan residents have only 10 minutes to escape. A short earthquake (a minor aftershock) hits Busan before the sea starts receding from the shore, causing mass hysteria as people realize a tsunami is coming. Thousands run for their lives before the wave reaches Haeundae and continues into Busan. Dong-choon, Seung-hyun, his grandmother and others on the Gwangan Bridge are swept away by the sea. A telephone pole collapses, electrocuting everyone in the water, but Man-sik and Yeon-hee survive. Dong-choon awakens on the bridge, but when he tries and fails to light a cigarette and subsequently discards the lighter out of frustration, it falls into petrol leaking from a tanker, causing an explosion that severs the bridge in half, sending shipping containers flying into buildings on the shore.

Hyeong-sik jumps from a rescue helicopter and saves Hee-mi in the sea. When Hyeong-sik and Joon-ha are together on the rope, Hyeong-sik realizes the rope is about to break, and only one can go up to the helicopter. He cuts the connected rope and falls into the violent sea. The elevator Yoo-jin is trapped in floods with water, and she talks in tears to her daughter Ji-min on her phone. A worker saves Yoo-jin. On the roof, she meets Ji-min and Hwi. The two help their daughter get on a crowded rescue helicopter. Before the helicopter leaves, Hwi tells his daughter that he is her biological father. Yoo-jin and Hwi hug each other before another megatsunami kills them.

After the tsunami, a memorial service honors the thousands who died, including Hyeong-sik, Hwi, Yoo-jin, and Man-sik's uncle. Dong-choon finds out that his mother died and breaks into tears. Many help reconstruct Busan. Man-sik, while cleaning the ruins of Yeon-hee's restaurant, finds the red ribbon, meaning she accepted his proposal. The movie ends with a scene of Haeundae in ruins but in a hopeful atmosphere.

Distribution rights for Haeundae was sold to Hong Kong, Taiwan, India, Indonesia, Japan, Malaysia, Philippines, Singapore, Thailand, Vietnam, the Czech Republic, Slovakia, Russia, Germany, Hungary, France, Quebec, Brazil, the United Kingdom, Australia and Turkey.^[3][4][5][6] The film was released in South Korea on 22 July 2009. As of 20 September 2009, Haeundae had received a total of 11,301,649 admissions in South Korean theatres.^[7]

In English-speaking countries, the film was released as Tidal Wave (an incorrect term as such types of waves are actually caused by gravitational influences, not displacement of water). In the United Kingdom, the DVD was released on October 12, 2009 from Entertainment One.^[8]