Climate services have become the focus of major international coordination activities over the past few years. In 2012 the Global Framework for Climate Services (GFCS) was approved and will be led by several United Nations Agencies, to strengthen and coordinate existing initiatives and develop new infrastructure where needed to meet society’s climate-related challenges. At European level the European Commission has allocated almost 27 million Euros from 2012 to 2016 towards the science behind seasonal and decadal climate services effectively putting Europe at the forefront of the international effort in developing this field. One of the main challenges climate service will face is the bridging of the so called valley of death: the divide still existing between climate science and decision-makers. Managing the multiple boundaries between producers and users of climate information is now of crucial importance. The concept of codesign and more generally of co-generation of knowledge is key to success of the new generation of climate services which need to be perceived as being not only credible scientifically but also salient and legitimate. In order to improve on the current setup it is essential for researchers to work on topics which could directly impact on the decision making process. The paper presents some of the key challenges and open questions climate service science will face in the coming years.