A high-speed transportation system, the system comprising: at least one transportation tube having at least one track, the at least one transportation tube being at least partially arranged within a body of water; at least one capsule configured for travel through the at least one transportation tube along a travel path between stations; a propulsion system adapted to propel the at least one capsule through the at least one transportation tube; and a levitation system adapted to levitate the capsule within the at least one transportation tube, wherein at least a portion of the travel path is arranged in the body of water under a surface of the water; an underwater station; a support structure arranged on or above the surface of the body of water and in electromechanical communication with the at least one tube, wherein the support structure comprises a docking platform floating on the surface of the water, the docking platform being structured and arranged for allowing a boat or other non-water transport vehicle to have access to the underwater station; wherein an access channel connects the docking platform with the underwater station, wherein the access channel includes at least one elevator, wherein the underwater station is configured to receive cargo from the at least one elevator; wherein the system additionally comprises at least one active stabilizer comprising one or more motors for maintaining the at least one transportation tube at the predetermined depth and/or orientation, characterized in that the support structure provides secondary floatation support for the at least one transportation tube. at least one transportation tube having at least one track, the at least one transportation tube being at least partially arranged within a body of water; at least one capsule configured for travel through the at least one transportation tube along a travel path between stations; a propulsion system adapted to propel the at least one capsule through the at least one transportation tube; and a levitation system adapted to levitate the capsule within the at least one transportation tube, wherein at least a portion of the travel path is arranged in the body of water under a surface of the water; an underwater station; a support structure arranged on or above the surface of the body of water and in electromechanical communication with the at least one tube, wherein the support structure comprises a docking platform floating on the surface of the water, the docking platform being structured and arranged for allowing a boat or other non-water transport vehicle to have access to the underwater station; wherein an access channel connects the docking platform with the underwater station, wherein the access channel includes at least one elevator, wherein the underwater station is configured to receive cargo from the at least one elevator; wherein the system additionally comprises at least one active stabilizer comprising one or more motors for maintaining the at least one transportation tube at the predetermined depth and/or orientation, characterized in that the support structure provides secondary floatation support for the at least one transportation tube.