China is a collectivist nation that varies socially and culturally from most Western countries. Recently, the country has been an attractive destination for international students. A contemporary digital platform such as WeChat Moments (WMs) is a leading social media platform among locals and international students to communicate and interact in cross-cultural settings for various purposes, including maintaining friendships and establishing new social capital. Prior research has overlooked the beneficial effects of such domestic social media platforms on international students in China, especially for strengthening their existing friendship quality and guanxi networking. Based on the self-disclosure theory, this study examines the relationship between international students’ WMs use intensity, online self-disclosure, closeness to friends, and guanxi network building using data from 445 international students employing structural equation modeling. This study reveals that WMs use has a substantial effect on the formation of guanxi networks and that online self-disclosure mediates the connection between WMs use and friendship closeness and guanxi network building. Several theoretical and practical recommendations are provided in the context of the guanxi network.