The swimming pool, which will form part of the Odiseo casino and leisure complex, cantilevers 20 metres on each side of central supports.
According to Clavel Arquitectos this makes it the longest overhanging pool in Europe.
Studio founder Clavel Rojo took the first swim in the pool to mark the completion of its construction.
"Obviously the structure is totally safe but definitely there was some reluctancy to be the first to try it," added Clavel.
When the building is complete, the swimming pool will be located within an elevated forest that is being built as part of a leisure complex on the outskirts of the town of Murcia.
The forest, which will be enclosed by a latticework of pipes to help shade the plants, will stand on top of the three-storey building that will contain a casino, as well as a nightclub and restaurants.
Clavel hopes that the building can bring excitement to the city of Murcia, which was heavily impacted by the financial crisis.
Source: Tom Ravenscroft
