This is a brief history on how PASO came to exist as a regional organisation in the Pacific responsible for aviation safety and security oversight to its member states.

• 1998 - Pacific Forum Minister’s Decision to form a cooperative Regional Safety Oversight Organisation and started with a Steering Committee.
• 2000/1 – Steering Committee undertook Feasibility Study and presented to Ministers
• 2001/2 - Steering Committee wrote an Implementation Plan and commenced discussions with Asian Development Bank.
• 2002 - Vanuatu selected as location for the head office of PASO..
• Aug 2003 – PASO incorporated in Vanuatu and first meeting of PASO Council of Directors held.
• Sept 2003 – decision was made to draft an International Treaty
• Feb 2004 - Pacific Islands Civil Aviation Safety and Security Treaty, (PICASST), first draft circulated.
• 7 Aug 2004 - The PICASST was opened for signature at the Pacific Forum Leaders meeting with four signatories - Kiribati, Samoa, Tonga and Vanuatu.
• 12 May 2005 – Solomon Islands became the fifth signatory to the PICASST.
• 11 Jun 2005 – The PICASST officially entered into force with five nations as signatories. 
• 4 Oct 2005 – Papua New Guinea formally acceded to the PICASST.
• 15 Nov 2005 – Cook Islands formally acceded to the PICASST.
• 22 May 2006 – PNG and Kiribati formally acceded to the PICASST, following earlier signatures in August 2004.
• 20 Jun 2006 – Solomon Islands formally acceded to the PICASST becoming the fifth formal Party to the Treaty.
• 16 Mar 2007 – Niue acceded to the PICASST, becoming the 8th Party to the Treaty.
• 7 Jun 2007 – Nauru acceded to the PICASST, becoming the 9th Party to the Treaty.