With municipalities increasingly digitising and sharing data, the complexity and risks of cyberthreats are growing, requiring stronger local government cybersecurity measures. Inter-municipal collaboration (IMC) has been identified as a key strategy to enhance cybersecurity, and this study examines its impact on Swedish municipalities. A survey was conducted across all municipalities to assess the extent of IMC, and a Cybersecurity Index (CIX) was developed to measure their cybersecurity efforts. Our analysis evaluates cybersecurity strategies at different collaboration levels. However, the results show that while IMC is widespread, its expected benefits in strengthening cybersecurity are not empirically supported, even for smaller municipalities. The study also highlights risks to public service resilience when municipalities become overly dependent on collaboration. Given the reliance on unproven collaborative solutions, these findings suggest a critical re-evaluation of IMC strategies in municipal cybersecurity management.