In a joint statement, the foreign ministers said the Arbitral Tribunal's 2016 Award in the Philippines-China arbitration is "final and legally binding by both parties".
ASEAN and China on Sunday approved the framework for a code of conduct in the West Philippine Sea/South China Sea and targeted to start the negotiations on the actual code by the end of the year.
Australia, Japan and the United States also "voiced their strong opposition to coercive unilateral actions that could alter the status quo and increase tensions".
The three countries are not claimants but have always been vocal on the issue, arguing their interest is in ensuring freedom of navigation and overflight.
The top ministers of Japan, the United States and Australia on Monday lambasted China's military buildup in the South China Sea and confirmed the importance of security cooperation in dealing with a territorial dispute in the waters.
The three nations also called on China and the Philippines to respect last year's arbitration ruling.
Several ASEAN countries want the code to be legally binding, enforceable and have a dispute resolution mechanism.
Their remarks, aimed at taming aggression in the disputed waters, are considerably stronger than a joint statement of concern issued by ASEAN, a 10-nation bloc whose economies depend heavily on China.
In a statement, Minister Wang Yi said they will cooperate if other non-Asean member countries will not interfere.
Coastal countries had "fully recognized the progress we have made through concerted efforts from all parties", he said.
Critics say the outline of key principles is lopsidedly in China's favor and suspect that Beijing may have consented to it to divert protests as it tries to complete and fortify man-made islands in the South China Sea with a missile defense system.
During the trilateral meeting Monday, Kono, a graduate of Georgetown University in Washington, D.C., spoke with Tillerson and Bishop in English, a Japanese government official said, a rare move for Japan's foreign minister.
Another diplomat says the wordings on the South China Sea issue to be included in the communique had not yet been finalized Saturday.
The sanctions resolution, which China and Russian Federation voted for, was the seventh the Security Council has imposed on North Korea since 2006, when the country carried out its first nuclear test. "At this time, if you ask who is carrying out reclamation, it is definitely not China - perhaps it is the country that brings up the issue that is doing it", he told Reuters. Satellite images have shown that Vietnam has carried out reclamation work in two sites in the disputed seas in recent years.