The aim of this study is to examine to what extent and in what ways Thai and other languages, especially English, are used in the rapid transit system in Thailand and to describe the bilingual strategies used. The data were collected through photographs of advertising signage in the BTS2 Skytrain system and open-ended interviews. Three stations, Mochit, Payathai and Siam, were selected to be analyzed. The results revealed that the majority of the signs (65%) are in bilingual Thai and English by script. On the whole, the Thai language is used for informational purpose, while English is used for symbolic function to express senses of luxury, technological advancement and internationalism. It is found that there are many types of code-mixing, the combination of English and Thai script, lexicon, syntax and phonology. To supplement the quantitative data, key players (i.e., advertising employees) were interviewed, who stated that the reasons for inclusion of English language in advertising are stylishness and flamboyance.