Method for air drying a fouled net portion of a net comprising the fouled net portion and a clean net portion in a circular sea pen. The method includes the steps of: a) fastening lifting posts to the pen on a drying side; b) attaching slidingly internal ropes to the net; c) fitting winches to the lifting posts on a drying side; d) connecting an energy source to the winches; e) releasing a suitable part of a clean net portion from a handrail; f) fastening the internal rope to a winch; g) bringing a part of the fouled net portion into the air by pulling the internal rope with the winch; h) fastening a part of the fouled net portion to the handrail; and i) repeating steps e)-h) until the complete fouled net portion is lifted into the air. The invention regards also lifting posts to carry out the method.