A submersible connector has releasably mateable first and second connector units. The first connector unit has at least one electrical pin extending through a bore in a retaining base and projecting outward from the forward end of the base. The second connector unit has at least one electrical socket module which receives a forward portion of the electrical pin when the units are mated. A pin seal device is located in one of the connector units and has a through bore which engages part of the pin at least in the mated condition of the units. The seal device has a first and second seals in sealing engagement with portions of the connector units when mated, and a chamber between the seals extends over an opposing portion of the pin at least in the mated condition of the units.