The front office (FO) department manages reservation, registration, room and rate assignment, guest services, room status, concierge and bell service. The department services are crucial in developing a tourist accommodation into a low-carbon accommodation such as hotel, resort and others. The purpose of this study is to discuss the content validity of instruments for low-carbon tourist accommodation indicators in the FO department of hotels. Based on the theoretical framework, there are 53 indicators frequently used in constructing low-carbon FO instruments. The study employed the Item Content Validity Indexes (I-CVI) analysis method and mean analysis to assess content validity. The method comprised item clarity, language appropriateness, and score scale using a five-point Likert scale to analyze expert evaluations of items using a questionnaire form. The instrument was assessed by a panel of six professionals in tourism, hospitality, and industry involved in low-carbon research. An instrument is accepted and has a good level of content validity when it exceeds the take-off value of ≥ 0.80. One item was excluded from the instrument as it did not reach the take-off value. The average mean results of each expert review on the items ranged from 3.41 to 5.00, suggesting that no questions required repetition. Overall, 17 items were refined by fitting the items to the FO department work scope. The findings revealed that the instrument was acceptable and relevant. It provides an original and useful indicator to measure the low-carbon approach in the FO department of hotels as to achieve the agenda of low carbon tourism.