Inter-continental Liquefied Natural Gas (LNG) trade can facilitate the development of a global natural gas market. However, in addition to explicit shipping costs, such trade requires time commitments in shipping due to the long hauls of many shipping mutes. We show that this time commitment adds an additional economic cost to LNG shipping, and creates a positive relationship between the economic cost of LNG trade and regional natural gas price spreads. Necessary time commitment therefore augments the other costs of LNG trade. and contributes to weaken the ties between global natural gas markets.