Conditional cooperation between boat owners and fishermen in Kramat Village, Bungah District, Gresik Regency has become a common practice to overcome fishermen's limited access to capital. However, the implementation of this cooperation involves several conditions that may create an imbalance of rights and obligations between the parties. This study aims to analyze the practice from the perspective of fiqh muamalah, particularly based on the concept of mudharabah and the principles of justice (al-'adl), balance (at-tawazun), public welfare (maslahah), and la dharar wa la dhirar. This research employed a qualitative field research approach. Data were collected through interviews, observations, and documentation involving boat owners, fishermen, and local religious leaders, and were analyzed descriptively using the framework of fiqh muamalah. The findings reveal that the cooperation practice shares characteristics with a mudharabah muqayyadah contract because the capital owner imposes specific conditions on the business manager. Nevertheless, its implementation does not fully comply with the principles of fiqh muamalah, as fishermen are required to bear repair costs for assets owned by the boat owner and must sell their catches to the owner at prices below the market value. Despite these shortcomings, the cooperation still provides employment opportunities and income for fishermen who lack fishing capital. Therefore, improvements to the cooperation mechanism are necessary to better reflect the principles of justice, balance, and public welfare in Islamic commercial jurisprudence.