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.
• 3 Aug 2007 - Vanuatu and PASO signed service agreement
• 18 Oct 2007 - Nauru and PASO signed service agreement
• 7 Nov 2007 - The Memorandum of Understanding Relating to the Pacific Aviation Safety Regulatory Oversight between the Ministry of Foreign Affairs and Trade (MFAT) and Civil Aviation Authority (CAA) and Pacific Aviation Safety Office (PASO) was signed
• 16 Nov 2007 - Tonga and PASO signed service agreement
• 20 Nov 2007 - Solomon Islands and PASO signed service agreement
• 25 Apr 2008 - Tuvalu acceded to the PICASST, becoming the 10th party to the Treaty
• 19 May 2008 - The working arrangement relating to the provision of advise and assistance on matters relating to civil aviation safety and security between CAANZ and PASO was signed
• 14 Jul 2008 - Papua New Guinea and PASO signed service agreement
• 15 Oct 2008 - PASO and CASA signed the working arrangement relating to the provision of advise and assistance on matters pertaining to Civil Aviation
• 2009 - PASO and CAAFI (Fiji) signed the working arrangement
• 1 Oct 2010 - PASO signs MOU with the Carribean Aviation Safety and Security Oversight System (CASSOS)