An underwater watercraft including a passenger compartment and an ingress/egress port in which the watercraft has buoyancy and center of gravity adjusted to maintain a generally level or other desired attitude when submerged, and an optionally angled attitude at a water surface for ingress/egress. The attitude is also adjustable via the placement of ballast and optionally including a movable ballast that adjusts the location of the center of gravity as desired. The ingress-egress port optionally includes an entry elevated from a main passenger compartment and including a riser and optionally removable or concealable handrails. The ingress-egress port has an angled orientation in a submerged mode, and an optional orientation generally parallel to the water surface or angled but above the surface in a surface mode.