301 redirects are important in Magento SEO because they help maintain the integrity and consistency of a website's URL structure. When a webpage is moved or deleted, its URL is changed, which can cause broken links and negatively impact search engine rankings. A 301 redirect directs users and search engines to the new URL, indicating that the old page has permanently moved to the new location. This helps preserve traffic and link equity, and ensures that search engines continue to crawl and index the website effectively. In Magento SEO, it is important to implement 301 redirects when setting up new URLs or restructuring existing ones to avoid any negative impacts on rankings and user experience.