The 13-member contingent received a warm welcome at the airport and includes eight players from the T20 squad and five members of the team management.
The remaining five players of the Sri Lankan squad are expected to arrive in Islamabad separately.
Pakistan and Sri Lanka will play a three-match T20 series, with all matches scheduled to be held at the Rawalpindi Cricket Stadium.
The opening match will be followed by the second and third games as the two teams compete in the T20 series in Pakistan.