A bit more info about what goes into the DDS: There are basically two bulky items that I'm aware of -- one is the rubber raiding craft used by special operators and others all over the world, and the other is the SEAL Delivery Vehicle (SDV), which is a minisub with 2 operators which can carry 4 SEALs.
The SDV has been progressively improved over the years with more speed and longer underwater range. It's not really all that "mini" with a length of 22 feet and an underwater speed of 6 knots max. Apparently there are armed versions as well; information on Special Operations gear is a bit tough to come by.
It appears to me that the SDV Mark 8 has been replaced by the SDV Mark 11. (3rd & 4th photos) Major differences in the two include the use of Lithium-ion batteries in the later model and a greatly increased operating depth -- the Mark 8 is a shallow-water model, while the Mark 11 can go down considerably deeper.
https://en.wikipedia.org/wiki/SEAL_Delivery_Vehicle