The order was placed with Japan's Mitsubishi Heavy Industries, and the tanker is to be delivered in the second half of 2016, Astomos Energy said, adding that the new VLGC will replace an older tanker in its fleet.
The Panama Canal Authority is targeting January 2016 for the expansion startup, but the market expects it sometime later that year.
The latest move is part of Astomos Energy's plans to scrap tankers that are 20-25 years old and build new VLGCs to replace them, while it also maintains or expands its use of chartered vessels to have a competitive and stable fleet amid expected increases in LPG output from the US and West Africa.
This is Astomos' third order this year for a vessel that can transit the expanded Panama Canal.
Astomos' previous orders were placed in March and July for VLGCs to be delivered in Q1 2016 and Q4 2016.
In December, Astomos placed two other orders for building new VLGCs that can transit the expanded Panama Canal. Those vessels are scheduled to be delivered in Q4 2015 and Q1 2016.
The vessel in Astomos Energy's latest new tanker order will be part of a fleet that is time-chartered and operated by Japan's Iino Lines, the company said.
As of September, Astomos Energy has a total of 21 VLGCs in its fleet, of which six are its own vessels and the other 15 are time-chartered tankers.
The company aims to expand its LPG fleet to around 30 VLGCs by 2020, Astomos Energy president Osamu Masuda said in April.
Editor's Comment: Just another example of a trickle-down resulting from Panama's decision to expand the Panama Canal.