Eurostar says it has carried more than 130,000 extra passengers since the launch of direct services between the British and Dutch capitals in April.
A third service will be introduced in June to meet demand on the route, recognising commitments from the British and Dutch governments to have security checks and border controls in place at Dutch stations by the end of 2019.
Currently passengers travelling to London have to change trains at Brussels South, where customs and security checks are carried out.
Eurostar says that it plans to add a fourth daily service as soon as the new border control arrangements are in place for travel from the Netherlands to Britain, with ambitions to increase frequencies to five trains a day in the longer-term.
Eurostar currently offers a journey time of 3h 1min between London St Pancras and Rotterdam Central, with trains reaching Amsterdam in 3h 41min.