This dive site is the historic Ojamo Mine, an 18th-century lime mine located near Lohja, Finland, that has been a popular diving destination for nearly 40 years. Divers explore an intricate network of flooded tunnels and chambers, offering a unique opportunity to experience an underwater industrial landscape. Navigation within the mine requires specialized training and careful planning due to the overhead environment and potential for disorientation in the complex passages.
While the mine itself is largely devoid of marine life, the quarry is connected to Lake Lohja, where the shallow open water areas frequently host freshwater fish. Divers and snorkelers in these parts might encounter common species such as perch and pike. However, these fish are generally not seen within the deeper, darker tunnels of the mine.
The best time to visit Ojamo Mine is typically during the warmer months when surface conditions are more comfortable, although the water temperature within the mine remains consistently cold year-round. Divers must be prepared for cold water, requiring appropriate dry suits and thermal protection. Due to the challenging overhead environment and depth, this site is strictly recommended for experienced and specially trained technical divers. Freedivers can explore the open water sections, but mine entry requires advanced skills.
