Yes. From LHTR 1.3 page 23:
Loading and Offloading: A transport can load
cargo before, during, and after it moves. A
transport can pick up cargo, move 1 sea zone,
pick up more cargo, move 1 more sea zone, and
offload the cargo at the end of its movement.
It may also remain at sea with the cargo still
aboard (but only if the cargo remaining aboard
was loaded in a previous turn or was loaded
this turn in the noncombat move phase). A
transport can offload into a hostile territory
only during an amphibious assault (see below).
Whenever a transport offloads, it cannot move
again that turn. If a transport retreats, it
cannot offload that turn. A transport can
never offload in two territories during a
single turn, nor can it offload cargo onto
another transport. If a sea zone contains
hostile units, the transport may not load or
offload in that sea zone (unless the only
hostile units are submerged submarines).