Early mobilization (EM) is acknowledged for its safety and benefits in the recovery of critically ill patients, yet its implementation in intensive care units (ICU) remains inconsistently aligned with established guidelines. This discrepancy highlights a gap between theoretical endorsement and practical application. While barriers to EM have been extensively studied, the intentions and perceived practices of ICU nurses towards EM, especially in certain geographical regions, have not been adequately understood. The objective of this study is to assess the perceptions, actual practices and intentions of ICU nurses regarding the implementation of EM for patients in the ICU setting. A cross-sectional, multi-centre, survey-based study. The study collected data through an electronic questionnaire from 227 ICU nurses across eight hospitals in Beijing, China, concerning their experiences, practices and intentions related to EM. The survey response rate was 50% (114 of 227), indicating a moderate level of engagement by the target population. Among the surveyed participants, 68.7% (n = 156) reported having experience with EM for critically ill patients. Of these experienced nurses, 49.3% (n = 77) indicated they carried out EM less frequently than once per week, while only 29.5% (n = 46) reported dedicating more than 20 min to EM activities per patient. Only 24.2% (n = 55) of participants confirmed the presence of specific EM guidelines in their workplace. Notably, guideline adherence could be influenced by the patient's condition severity, which may affect how these protocols are applied. Notably, the approach and frequency of EM practices showed significant variation across different ICUs. A substantial majority (75%, n = 170) of participants expressed a strong intention towards implementing EM, correlating significantly with factors such as having a higher education level (bachelor's degree or higher), receiving departmental support, encountering fewer perceived barriers, and belonging to specific departments like respiratory (SICU) and surgery (RICU). The EM guidelines mentioned by participants were primarily focused on specific protocols and guidance, highlighting the emphasis on structured approaches to EM in their clinical settings. Despite the recognized experience with EM among ICU nurses, there is a notable divergence between their practices and the recommendations outlined in EM guidelines. This study underscores the need for the establishment of clear, actionable guidelines, alongside the provision of targeted educational programmes and robust support systems, to foster the consistent and effective implementation of EM in ICU settings. This study underscores the clinical relevance of EM in ICU settings, advocating for the development of precise EM guidelines to improve patient outcomes.