In August 2018 a single draft negotiating text for a South China Sea Code of Conduct (COC) was first put forward with an agreement reached by China and ASEAN to finalise the COC within three years, starting from 2019. Having faced frequent tensions in the South China Sea, the agreement demonstrates that an effective diplomatic mechanism to manage the South China Sea dispute is possible. This paper firstly reviews some hurdles challenging the progress of a legal binding COC. So far, COC talks are marked by little progress and continuing differences. The paper concludes with an in-depth discussion on possible promises that Vietnam could take to change the situation and advance the outcomes of COC negotiations.