Abstract
<jats:p>Theoretical context and research gap The monograph The sea as a border and a space of cooperation: The cross-border maritime tourism space of the Baltic Sea Region explores the Baltic Sea as a dynamic and relational border space shaped by changing political, social, and institutional processes. The study builds on contemporary border theory, which conceptualises borders not as static or purely territorial lines but as constantly produced, negotiated, and transformed through social practices and political contexts (Paasi, 1996; Newman, 2006; Rumford, 2006). This understanding is particularly relevant in the maritime environment, where borders do not consist of visible physical markers but are constructed through legal frameworks, symbolic meanings, and functional infrastructures (UNCLOS, 1982; Grotius, 2009). Maritime borders thus operate differently from land borders: they are fluid, multifunctional, regulated through multilevel governance, and embedded in historical narratives of both division and exchange. The Baltic Sea Region (BSR) exemplifies these complexities. Historically marked by geopolitical fragmentation, especially during the Cold War, the region has transformed into a laboratory of cross-border cooperation following the political changes of 1989‑1991 and the subsequent enlargement of the European Union (Browning & Joenniemi, 2004; Kern, 2011). Processes of debordering, facilitated by the Schengen regime and EU cohesion policy, enabled increasing mobility and interaction, while moments of rebordering continue to appear in response to geopolitical tensions and changing internal regulations (Newman, 2006; Sohn, 2014; Wassenberg, 2020). The Baltic Sea is therefore an instructive case for examining the shifting nature of borders in contemporary Europe. Tourism is positioned as a sector closely intertwined with these transformations. Beyond its economic significance, tourism contributes to cross-border interaction by stimulating mobility, generating interpersonal contact, and shaping shared imaginaries of place (Timothy, 2001; Hall & Page, 2014). Scholars increasingly recognise tourism as a factor influencing region-building and the softening of borders, particularly in regions where environmental, cultural, and historical characteristics transcend national lines (Prokkola, 2008; Dołzbłasz, 2017). However, despite the Baltic Sea Region’s advanced cooperation structures and its growing role within the EU Strategy for the Baltic Sea Region (Medeiros, 2018; Studzieniecki, 2022), the maritime dimension of tourism cooperation remains significantly understudied. The monograph identifies three interrelated research gaps. First, an empirical gap: although Interreg IV A, B, and C programmes have been key drivers of territorial cooperation in the BSR, no comprehensive study had analysed tourism-related projects across all strands in a systematic, multi-scalar manner. Existing analyses tended to be fragmented, sector-specific, or limited to selected border pairs. Second, a spatial gap: the lack of GIS-based, topological, and cartometric analyses meant that the structure, density, and spatial differentiation of maritime cooperation networks had not been mapped or quantified, in contrast to the more developed literature on land borders (e.g., Więckowski, 2010b; Więckowski & Cerić, 2016). Third, a conceptual gap: tourism across maritime borders had not been theorised within the framework of borderingdebordering-rebordering processes, nor considered systematically as a mechanism contributing to transboundary region-building. The monograph responds to these gaps by developing a holistic conceptualisation of the cross-border maritime tourism space of the Baltic Sea Region. Methodological approach and empirical findings To address these gaps, the study employs a mixed-methods strategy integrating spatial analysis, statistical data, and qualitative evidence. The quantitative component includes a complete inventory and analysis of all tourism-related Interreg IV A/B/C projects implemented in the BSR between 2007 and 2013, offering a rare opportunity to examine tourism cooperation from a regional, programme-wide perspective. GIS-based mapping is used to identify the geographical distribution of beneficiaries, project clusters, and cooperation pathways. Cartometric methods allow for precise calculation of distances between partners, showing how cooperation unfolds in a maritime environment where physical adjacency does not exist. Statistical analyses of budgets, thematic orientations, leader-partner configurations, and cross-border linkages provide additional insight into the organisational logics of cooperation. The qualitative component consists of in-depth interviews conducted in 2019 with beneficiaries involved in selected tourism projects. These interviews illuminate motivations, partner selection processes, cooperation challenges, and perceived effects, adding interpretive depth to the spatial and statistical findings. The quantitative results reveal distinct spatial patterns within maritime tourism cooperation. Project activity is heavily concentrated in coastal regions with strong institutional capacities and established experience in EU cooperation, particularly in Sweden, Germany, Finland, Poland, and the Baltic States. These areas function as central nodes in the maritime cooperation network, reinforcing their position as regional leaders. The GIS analysis shows that cooperation often spans long maritime distances, underscoring that functional connectivity – transport availability, thematic complementarity, and institutional networks – plays a more important role than geographic proximity. This contrasts with land-border contexts where adjacency typically shapes cooperation intensity. Leadership asymmetries emerge clearly: partners from “old” EU member states frequently serve as project leaders, while organisations from “new” EU countries participate more often as partners. This pattern reflects broader disparities in administrative resources, project management expertise, and access to funding. The thematic structure of projects shows a strong emphasis on cultural heritage, coastal and maritime tourism products, sustainable development, environmental management, and marketing initiatives – topics tied closely to shared regional assets and environmental conditions. Spatial inequalities are evident across the Baltic Sea Region: western and northern areas of the BSR exhibit higher integration levels compared to certain eastern and southern subregions. These disparities highlight varying levels of preparedness, administrative maturity, and experience in cross-border cooperation. The qualitative interviews substantiate and deepen the quantitative findings. Respondents consistently emphasise motivations rooted in knowledge exchange, professional development, competitiveness, and the recognition of shared challenges, especially environmental issues and tourism seasonality. Partner selection is shaped by thematic complementarity, organisational reputation, trust, and previous cooperation experience, rather than by geographic factors. However, several constraints also emerge. Interviewees note barriers such as administrative complexity, differences in institutional culture, language-related challenges, funding asymmetries, and the logistical difficulties of managing cooperation across sea distances. Despite these difficulties, participants perceive cooperation as highly valuable, citing increased visibility, improved competencies, new tourism products, and the establishment of long-lasting relationships. The long-term effects extend beyond individual projects, contributing to institutional learning, durable networks, and interpersonal bonds, all of which strengthen relational capital across the Baltic Sea Region. Interpretation and theoretical contribution Building on these findings, the monograph proposes a model of cross-border maritime tourism integration, synthesising empirical evidence with the theoretical frameworks of border transformation and regional integration. The model highlights the distinctive mechanisms that shape cooperation in maritime borderlands. First, it emphasises the primacy of functional networks in regions lacking territorial contiguity. Cooperation across the Baltic Sea depends not on adjacency but on institutional capacity, thematic synergy, and transport connectivity. This insight demonstrates the need to conceptualise maritime borderlands in relational rather than territorial terms. Second, the model underscores the crucial role of EU territorial cooperation mechanisms, especially Interreg IV, in enabling cross-border collaboration in environments where natural borderlands do not exist. EU funding acts as a structural catalyst for cooperation, providing incentives, resources, and platforms for long-term networking. Third, shared environmental and cultural challenges serve as a basis for cooperation and help nurture a sense of regional identity. These shared issues, and the narratives surrounding the Baltic Sea itself, create a symbolic framework that strengthens cohesion. Fourth, the model integrates the dynamics of bordering, debordering, and rebordering, illustrating how cooperation responds to changing political, regulatory, and institutional contexts. Maritime cooperation is shown to be resilient but sensitive to fluctuations in openness and institutional frameworks. Finally, the model identifies clear spatial differentiation within the BSR, showing that integration progresses unevenly due to disparities in capacity, resources, and historical cooperation experience. Collectively, these insights advance several research fields. The monograph extends border theory into the maritime domain, provides new conceptual foundations for tourism geography, enriches European integration studies, and introduces innovative methodologies to regional science and spatial analysis. Limitations, future research and conclusion Several limitations frame the scope of the study. The analysis focuses on the 2007‑2013 Interreg period, which, although analytically coherent, does not capture more recent geopolitical and institutional developments. Gaps in project documentation also pose challenges for comparative analysis. Furthermore, the structural and functional differences between maritime and land borders complicate direct comparison. The monograph outlines future research directions including longitudinal analyses of post- 2013 cooperation, deeper examination of non-EU actors, and comparative studies of other maritime regions, which would help test the applicability of the proposed model beyond the Baltic Sea. In conclusion, the study demonstrates that the Baltic Sea has undergone a fundamental transformation from a separating line to a space of cooperation. Tourism, embedded within multiscalar governance and supported by EU programmes, plays a central role in this process. The emergence of a cross-border maritime tourism space is a cumulative outcome shaped by networks, institutions, shared challenges, and evolving regional identities. By combining rigorous empirical analysis with a robust theoretical model, the monograph offers a comprehensive framework for understanding how maritime borders can become engines of regional integration.</jats:p>