This qualitative study explores communication where English is the 'third' language used between participants whose cultures are different. The purpose was to investigate the communication experiences of Thai Immigration Police Officers (ITIPOs) and travellers to understand TIPOs' role within an orgnaisational and cultural context. I took a Thai culture-centred approach incorporating Thai values, Buddhist teachings, the organisational context, and TIPO's communication goals in the interactions. My thesis is that individual language skills, communication competence and goals, organisational roles and functions, and Thai cultural values influence communication at the border. Data-collection methods included: (1) Semi-structured interviews with 18 TIPOs and 71 travellers at five immigration offices in two Thai provinces (January-April 2018); (2) Documents from the Thai Royal Police and Thai Immigration Bureau that informed the TIPO role. The thematic analysis resulted in three main findings. The first finding centred on TIPO and travellers’ perceptions of each other's communication politeness. Results suggest that TIPOs' English-language competence influenced travellers' perceptions of the TIPO’s ability to communicate politely. Travellers saw TIPOs’ competence in spoken language as essential for TIPOs to communicate successfully with them. Also, travellers perceived politeness in TIPOs’ ability to engage in relational communication rather than just focusing on the task. This finding has implications for TIPOs’ communicating relational and identity goals at the border. Limited English-language competence impacted TIPOs' ability to communicate politely (relational goals), undermining their identity communication goals to be seen and respected as police officers. The second finding concerned the influence of the role requirements for TIPOs in their interactions with travellers. First, TIPOs needed to enact Buddhist values upheld by the Thai Royal Police and Thai Immigration Bureau while managing the power distance between themselves as law enforcers and travellers. Second, TIPOs needed to enact a “service mind” when serving travellers while exercising the authority inherent in the role. The implications centre on TIPOs communicating their instrumental, relational, and identity communication goals; that is, they need to be seen as Thai Immigration Police (identity) while simultaneously enforcing the law (task) and serving the traveller (relational). The third finding featured the practicalities, benefits, restraints, and opportunities for TIPOs in enacting Thai values and Buddhist teachings in their service provision interaction with travellers. At the interaction level, TIPOs responded to travellers' communications with Thai terms incorporating Thai values. However, the TIPO’s responsibility to enforce the law constrained TIPOs in fully enacting Thai values and Buddhist teachings. Even so, TIPO had some latitude in observing Thai values. The findings have implications for organisational commitment to Thai and Buddhist values (identity goals) and support for TIPOs to serve travellers (relational goals) in carrying out tasks associated with enforcing the law (instrumental goals). Taking a Thai culture-centred approach to investigate TIPO-traveller interactions at the border, was significant in revealing the task, identity and relational communication challenges for TIPOs in enacting their role. Further research opportunities lie in investigating how the organisation’s values, processes and training can help TIPO in managing such challenges at the border.