Conservation programs in Kepulauan Seribu National Park (TNKpS) need communication space in order to attract target group participation, It is necessary for for community of fisherman to talk each regarding conservation policies addressed to.Public sphere defines asa freepolitical and economic domination elements space, existing public sphere in TNKpS have physical or non-physical characteristics, actors either co-opted or not co-opted, and their political public sphere either authentic or un-authentic.There was a two-way dialogical communicatio in public sphere. Dialogue in the public sphere was seen from five types: technical dialogue, debate, genuine dialogue, reconciliation and critical, the results show only the genuine dialogue that occurred.Five obstacles in dialogical communication did not occurred to traditional small fishermen, they were not protective nor defensive to information and were mostly concerned with appropriate information, the time for dialogue is enough. Obstacles tendency to evaluate occurs in critical fishermen. Keyword: conservation, dialogue communication, environmental communication,national park, public sphere