Saint Kitts and Nevis:
none
Saint Lucia:
none
Saint Pierre and Miquelon:
none
Saint Vincent and the Grenadines:
none
Samoa:
none
San Marino:
none
Sao Tome and Principe:
none
Saudi Arabia:
none
Senegal:
897 km
note: 785 km on the Senegal river, and 112 km on the Saloum river