ABSTRACT: Aligning with the broader discussion of migration, seasonal migration also resembled a multifold phenomenon ranging from reasons of temporal movement to settling down process at the place of destination. In this paper, seasonal migration was portrayed in between the ‘alarmists’ view and ‘skeptic’ view of migration, holding a new position called ‘opportunistic migration’ that seemed to offer benefits to the seasonal migrants characterizing by gaining social knowledge and earning money from the place of destination. The empirical data, face-to-face in-depth interviews, showed that both social and economic aspects of seasonal migration were dominated by the pull factors, and environmental aspects were linked with the push factors. This paper also highlighted that social network played an active role for seasonal migrants, in particular, the workers who seasonally migrated into the brickfields of southwest coastal Bangladesh. While migrating from the rural to the urban context, two-tier verbal agreements took place in between the brickfield owners with the contractors, and the contractors with the brickfield workers. Though those verbal agreements seemed to contain some extent of the failure of expectations by the above-mentioned actors related to seasonal migration, it also held optimism of development for every actor. Finally, this paper reused the term ‘collateral promise’ with a slighter social tone to understand the informal interactions among the employers, contractors, and the seasonal migrants. KEYWORDS: Seasonal migration, social network, collateral promise, and qualitative method.