Access of Philippine traditional fresh/ice-chilled seining vessels to High Seas Pocket 1 (HSP-1) lessens fishing pressures in the Philippine Exclusive Economic Zone where juvenile oceanic tunas are more likely to be found. However, catch landed by carrier boats from HSP-1 were observed to be of reduced quality, thus eliciting lower market value. The present study was conducted to evaluate the efficiency of icechilled carrier boats by generating data on the magnitude of post-harvest losses incurred in landed catch from HSP-1. Exploratory Fish Loss Assessment Method and Questionnaire Loss Assessment Method were used to estimate quality losses. Landed catch of ice-chilled carrier boats from HSP-1 recorded an estimated loss of 17.25%. Key players incurred an estimated financial loss amounting to PHP 223 million (USD 4.3 million). Low quality catch commonly sold as raw materials for canning, smoking, and fishmeal processing entail cheaper prices, thus regarded as losses. A positive correlation was established between fishing duration and losses. Results indicate that the current preservation technique in carrier boats could induce quality deterioration in fish given the long distances and transit times involved. Thus, the use of carrier boats with freezing system should be allowed in HSP-1 to sufficiently preserve the quality of the catch. This will reduce losses in post-harvest fisheries, thereby increasing the potential income of HSP-1 players.