Świna tunnel (Tunel Świnoujście) has been completed and operational! Great news.

The underwater tunnel connects the Uznam and Wolin islands (previously only traveled by ferry). With 1484 meters length, the tunnel in Świnoujście is the longest underwater crossing in Poland. In the deepest place, it is 10 m under the bottom of the strait, which is 13.5 m deep in that place

The general contractor for this tunnel is the consortium of PORR, Gülermak and Energopol Szczecin. The contract was signed in September 2018. The construction of the tunnel was supported by the European Union with PLN 775.6 million with total cost PLN912m. The investor is the City of Świnoujście, and the General Directorate for National Roads and Motorways (GDDKiA) acts as a substitute investor. The works are done in 'design and build' method.

This tunnel interesting. Because entire crossing will consist of three parts. Each of these parts will be built using a different method. The one with a length of 475 m will be built in retaining walls, an open-pit technique will be used for the construction of 295 m, and the main part, 1.48 km long, will be bored by TBM. It will be a machine with a diameter of 13.5 m. Drilling to start in March 2021, and TBM will reach the final shaft on the island of Wolin in August of the same year.

I understand most critical work has been conducted by GÜLERMAK. The 13,4 meter diameter tunnel boring machine (TBM) used has been manufactured in China by CREG.

https://www.swinoujskie.info/2023/06/30/tunel-w-swinoujsciu-laczacy-wyspy-wolin-i-uznam-oficjalnie-otwarty/