In 1976 and 1978 he acquired the elderly passenger ships Gripen and Frisia II (renamed Nordshau and Nordpaloma) to start a ferry service between Neustadt and Rodby.

Also in 1976, Deilmann acquired the Norwegian Rost (renamed Nordbrise) and started a pioneer service between West and East Germany.

Whilst awaiting delivery, he also bought the Regina Maris, which was sold to Kuwait in 1982 for conversion into a large private yacht.

Following the insolvency of Peter Deilmann Reederei GmbH & Co. KG in 2009, with up to ten ocean and river cruise ships last, which had a turnover of around 50 million euros and around 50,000 passengers transported, was after the reestablishment of Reederei Peter Deilmann GmbH from 1 January 2010, the shipping company activity resumed.

In 2009 in the United Kingdom Peter Deilmann Cruises joined the Truly Independent Professional Travel Organisation (TIPTO) marketing consortium, becoming its 16th member.