- Sengal
- Senon
- Serialati
- Si Ipang
- Si Kubung Tausan
- Siasi Island
- Siawan
- Sibabag
- Sibago Island
- Sibakel Island
- Sibalan
- Sibaud
- Sibaung Island
- Sibihing Island
- Sibimbum
- Sibukllon
- Sibukut Island
- Sibuto
- Sibutu
- Sibutu
- Sibutu Group
- Sibutu Island
- Sicagot Island
- Sicalangcalong Island
- Sicio
- Sicolan Caloh Island
- Sicolan Island
- Siculigau Island
- Sicumbang
- Siet-Lake Higado