| Rank | Country | Waterways |
30 | Philippines | 3,219 km (limited to vessels with draft less than 1.5 m) (2007) |
| Pitcairn Islands | void |
28 | Poland | 3,997 km (navigable rivers and canals) (2006) |
94 | Portugal | 210 km (on Douro River from Porto) (2006) |
| Puerto Rico | void |
| Qatar | void |
47 | Romania | 1,731 km note: includes 1,075 km on Danube River, 524 km on secondary branches, and 132 km on canals (2006) |
2 | Russia | 102,000 km (including 33,000 km with guaranteed depth) note: 72,000 km system in European Russia links Baltic Sea, White Sea, Caspian Sea, Sea of Azov, and Black Sea (2006) |
| Rwanda | Lac Kivu navigable by shallow-draft barges and native craft (2006) |
| Saint Barthelemy | void |
| Saint Helena | void |
| Saint Kitts and Nevis | void |
| Saint Lucia | void |
| Saint Martin | void |
| Saint Pierre and Miquelon | void |
| Saint Vincent and the Grenadines | void |
| Samoa | void |
| San Marino | void |
| Sao Tome and Principe | void |
| Saudi Arabia | void |
63 | Senegal | 1,000 km (primarily on Senegal, Saloum, and Casamance rivers) (2005) |
80 | Serbia | 587 km (primarily on Danube and Sava rivers) (2005) |
| Seychelles | void |
72 | Sierra Leone | 800 km (600 km year round) (2005) |
| Singapore | void |
99 | Slovakia | 172 km (on Danube River) (2005) |
| Slovenia | void |
| Solomon Islands | void |
| Somalia | void |
| South Africa | void |
| South Georgia and the South Sandwich Islands | void |
| Southern Ocean | void |
64 | Spain | 1,000 km (2003) |
| Spratly Islands | void |
100 | Sri Lanka | 160 km (primarily on rivers in southwest) (2006) |
25 | Sudan | 4,068 km (1,723 km open year round on White and Blue Nile rivers) (2006) |
59 | Suriname | 1,200 km (most navigable by ships with drafts up to 7 m) (2005) |
| Svalbard | void |
| Swaziland | void |