For travelling from Phuket to Koh Samui by taxi, there will be either flat fare or metered fare.
Pre-computed, or flat fare can be more expensive but unlike buses and trains you do not need to buy a ticket for each passenger. If you are a group of 4 or less, you can take just one car – the fare is calculated on ‘per car’, not ‘per passenger’ bases.
This makes taxi a cheap option for travelling when in small groups..
If a taxi company offers larger vehicles like SUVs, it is a good idea to opt for it as it will be only slightly more expensive but will accommodate at least 6 passengers and enough space for your luggage. This makes it even more budget-friendly for groups and families.