This paper examines countries' free-riding incentives in international environmental agreements (lEAs) when, first, the treaty is non-enforceable, and, second, countries do not have complete information about other countries' non-compliance cost. We analyze a signaling model whereby the country leading the negotiations of the international agreement can reveal its own non-compliance costs through the commitment level it signs in the IEA. Our results show that countries' probability of joining the IEA is increasing in the free-riding benefits they can obtain from other countries' compliance, and decreasing in the cost of not complying with the initial terms of the agreement. This paper shows that, when free-riding incentives are strong enough, there is no equilibrium in which all countries join the IEA. Despite not joining the IEA, however, countries invest in clean technologies. Finally, we relate our results with some common observations in international negotiations.