S
- St. Christopher
- St. Helena
- St. Lucia
- St. Pierre et Miquelon
- St. Vincent
- Saint-Nazaire
- Samoa (German)
- Sarawak
- Sardinia Forged Stamps of Sardinia First Issue
- Forged Stamps of Sardinia Second issue
- Forged Stamps of Sardinia Third issue
- Forged Stamps of Sardinia Fourth issue 5c
- Forged Stamps of Sardinia Fourth issue 10c
- Forged Stamps of Sardinia Fourth issue 20c 40c 80c
- Forged Stamps of Sardinia Fourth issue 3 lire
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- Senegal-Niger
- Serbia Postes Serbes Overprint Corfu
- Seychelles
- Shanghai
- Sicily
- Sierra Leone
- Singapore
- Slesvig Plebiscit
- South Africa
- South Australia
- South West Africa
- Southern Nigeria
- Southern Rhodesia
- Spain 1850
- Spain 1851
- Spain 1852
- Spain 1853
- Spanish West Indies
- Stellaland
- Straits Settlements
- Sungei Ujong
- Suriname
- Swaziland
- Sweden
- Syria