A system for transferring at least one subterranean core sample under pressure can include a retrieval vessel that collects and houses the at least one subterranean core sample at a sampling pressure at which the at least one subterranean core is collected. The system can also include a linear actuator that couples to the retrieval vessel through a valve in the open position at a first time, where the linear actuator facilitates removal of at least one pressure barrier from the retrieval vessel through the valve at the first time while maintaining the sampling pressure of the at least one subterranean sample. The system can further include a testing vessel that couples to the linear actuator through the valve in the open position at a second time, and a hydraulic device that facilitates pressurizing the testing vessel to the sampling pressure at the second time.