The South China Sea (SCS) Two-Island Monsoon Experiment (SCSTIMX) is the observational task of an integrated project aimed to better understand interactions of convection over the SCS and Maritime Continent (MC) with large-scale flow. The project consists of sub-projects in three research groups: convective processes, large-scale dynamics, observations. SCSTIMX is one of the field campaigns of the Years of the Maritime Continent (2017-2020). Special observations made in the SCSTIMX are documented in this article that include field campaigns at Taiping and Dongsha islands during intensive observation periods (December 2017, March and May 2018), cruises by the National Taiwan University ocean research vessel (OR1) in December 2016 and December 2017, and satellite observations in the SCS-MC for the project years. We show the spatial-temporal evolution of the La Niña event from December 2016 to June 2018 and embedding interactions of convectively coupled equatorial waves (CCEW) with diurnal cycles and intraseasonal oscillations (ISO) in the SCS-MC. The La Niña-ISO-CCEWs together resulted in the late SCS summer monsoon onset in May 2018. In addition to the La Niña influence, the strong Indian Ocean dipole signal in December 2017 further weakened CCEWs in eastern Indian Ocean. We also show research highlights from participating projects published in the current special issue of TAO.