[19] On 15 August 1951, in reaction to China's exclusion from the talks, the PRC government issued the Declaration on the Draft Peace Treaty with Japan by the US and the UK and on the San Francisco Conference by the then Foreign Minister Zhou Enlai, protesting the absence of any provisions in the draft on who shall take over the South China Sea islands.

Article 2 of the document provided that "It is recognized that under Article 2 of the Treaty of Peace which Japan signed at the city of San Francisco on 8 September 1951 (hereinafter referred to as the San Francisco Treaty), Japan has renounced all right, title, and claim to Taiwan (Formosa) and Penghu (the Pescadores) as well as the Spratly Islands and the Paracel Islands.

The PRC claims it is entitled to the Paracel and Spratly Islands because they were allegedly seen as integral parts of China under the Ming dynasty.

Many countries including the United Kingdom, Australia, Italy, France, Canada, and Spain had made similar declarations to reject any of the procedures provided for in sections 2 of Part XV of the convention with respect to the different categories of disputes.

[25]: 121 In the arbitration, the Philippines contended that the "nine-dotted line" claim by China is invalid because it violates the UNCLOS agreements about exclusive economic zones and territorial seas.

[28] Its position was that because most of the features in the South China Sea, such as most of the Spratly Islands, cannot sustain life, they cannot be given their own continental shelf as defined in the convention.

[29] In framing its contentions, the Philippines' "submissions scrupulously avoided treading on questions of territorial sovereignty and boundary delimitation, which would fall outside the tribunal's" jurisdiction.

[25]: 123–124 China stated that several treaties with the Philippines stipulate that bilateral negotiations be used to resolve border disputes and that the Philippines of violating the 2002 ASEAN-China voluntary Declaration on the Conduct of Parties in the South China Sea, which also stipulated bilateral negotiations as the means of resolving border and other disputes.

[37] According to Ian Storey, a regional expert at the ISEAS–Yusof Ishak Institute, for decades, the common understanding among scholars was that "Itu Aba is the only island in the Spratlys".

The coast guard had already deployed a vessel to the area, and a naval frigate mission was pushed ahead of schedule in response to the ruling.

It agreed to take up seven of the 15 submissions made by Manila, in particular whether Scarborough Shoal and low-tide areas like Mischief Reef can be considered islands.

It also told Manila to narrow down the scope of its final request that the judges order that "China shall desist from further unlawful claims and activities.

[50][27] Conclusions expressed in the award included the following: The tribunal had considered the issues related to the maritime areas in South China Sea.

[70] There are countries and multinational bodies that have expressed support or opposition to the Philippines' move to take the South China Sea dispute to the Permanent Court of Arbitration.

Compiled from the Center for Strategic and International Studies,[80] the Council of the EU and the European Council,[81] and the Philippine Daily Inquirer[82] Within the Association of Southeast Asian Nations (ASEAN), Malaysia and Vietnam, who have territorial claims in the South China Sea, as well as Australia, Indonesia, Japan, Singapore and Thailand, sent observers to the proceedings.

[105][106] In June 2016, before the tribunal issued its ruling, Malaysia's foreign ministry released what it said was a joint statement of ASEAN expressing "serious concern" over land reclamation activities in the South China Sea.

"[108] Hun Sen suggested the case was a "political conspiracy" and that the ruling "will not be fair",[109] but also said that "Cambodia will just choose to stay neutral on this issue.

[117] European Council President Donald Tusk said on the sidelines of a summit in Ise-Shima that the bloc should take a "clear and tough stance" on China's contested maritime claims.

In April 2016, Foreign Minister Sushma Swaraj stated in a communique that Russia, India and China agreed to maintain legal order of seas based on international law, including the UNCLOS, and all related disputes should be addressed through negotiations and agreements between the parties concerned.

NATO supports any regional solutions based on political and diplomatic negotiations, "rules-based international system" and peaceful means for resolving discord.

[123] In July 2016, it was reported that more than 70 countries had called for the South China Sea dispute to be resolved through negotiations, not arbitration, although American media and think tanks have expressed doubt, with the Center for Strategic and International Studies (CSIS) via its Asia Maritime Transparency Initiative (AMTI) putting the number at ten.

Directly concerned states should resolve disputes through negotiation and consultation in accordance with all bilateral treaties and the Declaration on the Conduct of Parties in the South China Sea (DOC), the statement said.

"Korea has consistently stressed that the dispute must be peacefully resolved according to international agreements and code of conduct" and "China must guarantee the right of free navigation and flight.

[25]: 145 [168] Numerous Chinese celebrities expressed support online for China's position, which in turn prompted a broader public response.

[172] At the 24 July 2016 China-ASEAN Foreign Ministers summit, China assured ASEAN that it would not conduct land reclamation on the Scarborough Shoal.

[25]: 123  On 8 August 2016, the Philippines dispatched former president Fidel V. Ramos to Hong Kong to mitigate tensions following the arbitration result.

[25]: 129  Duterte and Chinese president Xi Jinping also created the biannual Bilateral Consultation Mechanism on the South China Sea, a process allowing the two nations to peacefully manage disputes and strengthen their relations.

[185] RAND Corporation analyst Derek Grossman observed that by June 2020, Duterte's hopes for more Chinese investments and loans had not materialized.

[175] During a speech at the UN in September 2020, Duterte affirmed the ruling, stating "the award is now part of international law, beyond compromise and beyond the reach of passing governments to dilute, diminish, or abandon.

"[187] The election of Philippine president Bongbong Marcos in 2022 saw the onset of worsening Philippine-China relations and frequent skirmishes in the South China Sea.