The firm says the move is designed to help maintain services to the UK in the event that severe weather or a localised Covid-19 lockdown prevents it running a crossing to the usual destination of Poole in Dorset.
Currently the only passenger service to Portsmouth – 55 miles east of Poole – is operated by the Commodore Clipper conventional ferry.
Condor confirmed that the trials, carried out by the Liberation, were conducted to add flexibility to services and stressed that the Poole service was not under threat.
They also said that during the berthing trials the high-speed ferry was used to film a scene in a new TV drama, the name of which has not been revealed.
In a statement, a Condor spokesperson said: ‘Condor Liberation was positioned to Portsmouth on Sunday as part of our operational contingency plan.
‘The purpose was to familiarise our team with handling one of our high-speed ferries if Liberation or Rapide were unable to berth in Poole due to inclement weather, or if the port was blocked for any reason.
‘This is similar to the trials we ran earlier this year with Cherbourg as an alternate to St Malo.’
The spokesperson added: ‘Flexibility in operations is prudent should there be a need to switch between either UK port due to a localised Covid-19 lockdown.
‘Liberation was also utilised in Portsmouth on Sunday by a production company filming a scene for an upcoming, national TV drama series.’