England's Luke Wright and Tymal Mills and South Africa's Rilee Rossouw announced their decisions to withdraw on Twitter, while Kevin Pietersen also indicated his season had ended.
All four play for Quetta Gladiators, who have made it to the March 5 final to be held in the eastern city of Lahore.
Pakistan has recently been hit by a spate of bombings and attacks that have killed more than 130 people nationwide.
"It's with a heavy heart I will not be coming to Lahore," all-rounder Wright said. "I have a young family and for me a game of cricket is just not worth the risk.
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"I'm sorry as I know how much it means to you all and hopefully in the future the safety will not be in doubt to come (and) play there."
Batsman Rossouw added: "For those still unsure it's with a sad heart that I must announce that I will not be taking part in the final,"
Pakistan have played most of their home internationals in the United Arab Emirates since 2009, when gunmen attacked a bus carrying Sri Lanka from their team hotel to Lahore's Gaddafi stadium, wounding six players and killing six security staff and two civilians.
The country has since been starved of international cricket, apart from a short visit by Zimbabwe in 2015.
(Reporting by Simon Jennings in Bengaluru; Editing by Ken Ferris)
