The role of tools and approaches is currently much debated in maritime spatial planning (MSP). Past evaluation has mainly concentrated on decision support tools and the tangible outputs these can provide for MSP, but little attention has so far been been given to the soft or indirect benefits tool use can have in MSP. This paper assesses the potential benefits of tool use in the context of four common integration challenges in MSP. Drawing on case study material from the Baltic Sea region, the paper reviews the potential contribution of five selected tools and approaches to multi-level and transboundary, policy and sector, stakeholder and knowledge integration. Specific end points are defined for each integration challenge, including general desired outcomes of integrated MSP processes as a template for assessment. Our review shows that the selected tools play different roles in moving towards the various end points of MSP integration. There is an important difference between the potential of each tool, or its inherent capacity, and how it is applied, e.g. in a participative or non-participative setting. Another lesson is that some integration benefits can be achieved by the tools alone, while others – often secondary benefits - depend on how the outcomes of tool use are taken up by the subsequent MSP process. Although the nature of a tool does restrict its potential contribution to MSP integration challenges, the secondary “soft” benefits that can be achieved through certain styles of application and good links to the MSP process can add important integration benefits up and beyond the tool itself. The results presented here may also be relevant to other types of spatial planning and conservation management.