The use of three-dimensional virtual worlds (3DVWs) in language education has been widely acknowledged in the field, and researchers have expressed a growing interest in their proliferation in second language (L2) learning and instruction. In order to improve the Thai-speaking abilities of learners of Thai as a foreign language (TFL) in three Asian nations, this study implemented collaborative tasks in the Redesign of Instruction for foreign Language and Communication Achievement (RILCA) World hosted by Second Life over a 10-weeks period. The participants were forty second-year undergraduate students enrolled in Thai courses in China, Japan, and Hong Kong. A pre-experimental design was employed, which involved administering a pretest measure, followed by ten identical collaborative tasks, and a posttest to each of the three classes in RILCA World. The results of the investigation demonstrate that the use of collaborative tasks in RILCA World can provide L2 learners with educational opportunities that are unrestricted by time and geography and enhance TFL speaking results. The implications of these findings for the applicability of 3DVWs and collaborative tasks in boosting foreign language speaking skills are highlighted. The collaborative tasks and insights presented in this study not only serve as a practical resource for TFL educational scenarios, but also contribute to the body of knowledge regarding a range of L2 learning and teaching in 3DVWs.