Islands Unlimited has postponed its first six days of sailings as it waits for operational permissions.
The first sailing on the 316 seater San Pawl was due to be today, 30 May, leaving Guernsey at 0700.
Passengers were told by the company yesterday that it had to cancel its sailings until Thursday 5 June:
"It is with regret that we have experienced delays to our operational readiness, which has impacted our ability to complete our obligations as required by the relevant authorities."
The company has apologised but says it has no choice but to postpone its launch date.
It was only two weeks ago that its 316 seater fast cat, the San Pawl, arrived in Guernsey aboard a special boat transporter.
Islands Unlimited has a twice daily inter island schedule with three sailings at weekends.
Water Taxi CI, a small boat company that is to run services between Jersey and Alderney, has said it will put on some charters this weekend to meet demand.

Marine life focus of special documentary screening in Guernsey
New clubhouse facilities for Guernsey's Victoria Park stadium
Those living with Dementia in Guernsey can take a virtual walk down memory lane
Anglers warned after litter and minor damage at Guernsey's main harbour
Alderney airlinks "operating as usual" following disruption
Guernsey's Wildlife Hospital nears completion
Guernsey's 50th Swimarathon raises more than £70,000
Scheme to help Guernsey residents cover rental deposits