"Crossing penalties
A crossing penalty that reduces all dice rolls is applied to attackers under the following circumstances:
Crossing a river: -1 to all rolls.
The presence of rivers between a province and its neighbors is indicated in the province window by a small river icon. The tooltip over this icon will show which neighboring provinces will be protected by rivers.
Crossing a strait: -2 to all rolls.
Amphibious landing: -2 to all rolls.
Includes attacks from sea or landing directly with ships at port.
For attackers that originate from multiple provinces, they will all receive the crossing penalty if any one of them would normally receive it alone. All crossing penalties are removed if the attacking leader has a higher maneuver rating than the defending leader. The check on leader maneuver rating is performed daily, so a high maneuver leader can still swing the tide of battle even if he joins an engagement late."
From the wiki
I would guess you will get the crossing penalty due to the wording above only explicitly mentioning "crossing" penalties.
Then again.. Amphibious landing is listed under crossing penalties.
