Island Levels are integral to upgrading the capabilities and upgrades of your Island. Your Island Level also determines your island top position. The higher your island level, the higher you will be on is top. If two islands have the same level their position on is top will then be determined by their island points, more information under the Island Points tab. Upgrading your island costs both money and Upgrade Tokens. The main source of Upgrade Tokens is from completing Expeditions and from event keys.