In a statement, the carriers said it will start offering the weekly services "in response to the continued strong trans-Pacific market demand and to further support the challenging service schedules for [the] North America West Coast."

The Puma service will debut with the MSC Bhavya calling on DaChan Bay in Shenzhen, China, on October 3, before calling on Shekou in Shenzhen and the Port of Long Beach. The Mustang service will start on October 16 with the MSC Anya calling on Shanghai before sailing to Long Beach. Both ships are 5,000 TEU.

MSC said the Puma and Mustang services will operate until further notice.

The MSC Bhavya previously served northern European and US East Coast ports, according to tracking data from AISLive. The MSC Anya served Mediterranean and eastern Canadian ports, the data shows.

Despite the additional ships coming to the trans-Pacific trade lane, the issue remains whether the additional capacity makes much difference to shippers. The record-setting congestion now gripping US West Coast ports and the resulting queue of vessels waiting to discharge has effectively soaked up much of the available capacity put into that market, according to market experts.