The purpose of this research is in examining the conditions in early-stage classroom adaptations and Korean language education for students returning to Korea after having lived abroad through the case study of Returnee Class at S Elementary School in Seoul, paying attention to the features as a Sheltered Program in the special classes for such students. In the Returnee Class as Sheltered Program the ultimate objective over the education period of a year or so is to help the students with insufficient capabilities of the Korean language to better understand the learning material and to assist with the classroom adaptation so that they may join a regular class soon, which in terms of the content was distinct from bilingual education or immersion English program targeted at maintaining international qualities, that are expected from the parents. However the Returnee Class as Sheltered Program has demonstrated that it can provide various layers of educational experience through its theme-based integrated curriculum, which was ran for the adaptation of returnee students in such areas as culture, school life, language and subject learning. Theme-based integrated curriculum was run based on Sheltered Content-Based Instruction, in which the core learning content is set as the Big Idea and these topics are linked to related content in various subjects so that language and subject content are naturally taught together. Also through the analysis of the Korean language class for returnee students it has come to light that teaching in this class was based on the learning objective in standard Korean language education curriculum using the regular Korean language textbooks, but the conditions in Korean language education had been adjusted to meet the needs of students whose Korean language skills are insufficient. The distinct features of the Returnee Class as Sheltered Program can be identified as providing comprehensible input, making sense of core concepts by explaining with English words, emphasizing the training of reading fluency through choral reading, emphasizing the meaning and usage of vocabulary, inducing in-depth learning by emphasizing metacognitive knowledge of Korean language, lowering the affective filter level of students by adjusting the speed of speech and teaching, and running class flexibly by restructuring the learning content and curriculum.