You may need a visa for Cambodia if you have a Seychellois passport
Visa options for Cambodia
Visa on arrival is required for trips longer than 15 days
Travellers need a visa to visit Cambodia for Business or Tourism for more than 15 days. Travellers do not need a visa if staying for 15 days or less. Travellers can get a visa on arrival in Cambodia at the port of entry, such as an international airport or border crossing.
This is not offered by sherpa°.
Apply on the government site.