Most visitors reach Loango through arranged transfers. The usual route is to fly to Libreville, continue to Port-Gentil or Omboue, then travel onward by boat or 4WD depending on the lodge, season, and road conditions. Independent travel is possible in theory but awkward in practice; permits, boats, and park access are much easier through a specialist operator.
Allow slack in your schedule. Weather, tides, and vehicle availability can change transfer times, and this is not a corner of Gabon where you want a tight same-day international connection.