This article explores the bilingual practices of a community of English-speaking Thai nationals on two online platforms: a social network site (Facebook) and an instant messaging service (MSN). Through a discourse analysis of informal conversation exchanges, the article examines the ways in which these participants play with the two languages and writing systems through practices of code- and script-switching as well as orthographic variation, and it shows how these practices contribute to the construction of interpersonal meaning, the negotiation of relationships, and the performance of social identity in these online contexts. One interesting finding which this study reports is that certain forms of orthographic variation occur not only in English but also in both romanised Thai and that written in the Thai script. This is in contrast to conclusions drawn in previous studies which find that non-Roman scripts are often imbued with values of tradition and purity and are therefore not open to the manipulation which characterises the use of the Roman script. The conclusion of this study is that, in the absence of paralinguistic cues online, the participants are drawing on all the semiotic resources available to them—including those supplied by different writing systems—in performing identities as modern, internationally-oriented Thais.