The project consortium said it deployed two barges to collect soil samples from the seabed about 3 miles off the southeastern Albanian coast.
Albert Haak, the country manager for TAP, said stressed the survey meets international standards on environment and safety.
"The comprehensive analysis of the seabed is necessary for TAP in order to decide on the exact offshore routing of the pipeline and also for further pipeline engineering work," he said in a statement.
Early this week, the consortium controlling Shah Deniz II natural gas field off the coast of Azerbaijan chose TAP as a possible route to European natural gas consumers.
TAP would transport as much as 700 billion cubic feet of natural gas per year to European markets through Greece and Albania and then through the Adriatic Sea to Italy.
The project is up against the planned Nabucco pipeline for Europe and a project that envisions an expansion of existing transit networks through Turkey. TAP is the shortest of the projects outlined in the so-called Southern Corridor of transit networks.