Tanguar Haor (TH) is considered one of the Ecologically Critical Areas (ECAs) of Bangladesh and is internationally recognized as RAMSAR wetland (2nd Ramsar site) known to provide multiple ecosystem services to the society. Nevertheless, multidimensional threats and stressors, the capacity to supply ESs, and the biodiversity of the TH significantly degrades and threatens this wetland’s conservation and sustainability. Although the legal framework promises the sustainable conservation of fisheries resources, information on the implementation scenarios of fisheries laws, regulations, and policies in the TH Ramsar are scant. By merging qualitative and quantitative data of primary and secondary sources, this research aimed to analyze the legal framework to check the effectiveness of regulations for non-conflicting fisheries resources and the sustainable conservation of the TH Ramsar. Primary empirical data were collected by employing Participatory Rural Appraisal (PRA) tools, i.e., 204 semi-structured questionnaire-based individual interviews with fishers, three focus group discussions, and 14 key informants’ interviews in three fishing villages in the TH. In contrast, secondary data was set by reviewing published literature and related official documents. Results showed that, due to weak enforcement with inadequate surveillance and poor implementation of the legal framework, there was a high non-compliance with fishing laws, rules, and policies. Destructive and prohibited fishing gears, e.g., the use of small mesh fine nylon nets (current jal), purse seine net (ber jal), and the harvesting during ban period-illicit catch were widespread in the study areas. In addition, catching undersized fish, fishing at the restricted areas (sanctuary area), and fishing during spawning seasons occur often. There is a crying need for a comprehensive legal and policy framework to contextualize the local context, ensure the proper implementation of the fishing laws and regulations, increase the managerial inefficiency of enforcing agencies, ensure livelihood support during the fishing ban, and afford good alternative income options are still significant issues for good governance in the Tanguar Haor ECA. Findings might help to identify the gaps and misunderstanding of the existing legal practice while submitting urgent attention to the need for drawing a comprehensive legal and policy framework (contextually modified according to the local context), taking initiatives and acting synchronously for proper implementation, and calling transdisciplinary collaboration and cooperation among the agencies that may ensure the non-conflicting use of the natural resources of the TH that can be also helpful for the better conservation of this Ramsar wetland.