When implemented properly, redirecting a URL should not negatively affect SEO. However, if the redirect is implemented improperly, it can negatively affect your site’s search traffic and rankings.
Here are a few tips to make sure you are properly implementing redirects:
1) Opt for a permanent 301 redirect
While there are a couple of different redirect options, such as a temporary 302 redirect or a meta refresh redirect, 301 redirects are the most effective to use if you want to maintain the old URL’s rankings and traffic. However, this is only true if you are permanently moving content from an old URL to a new URL.
2) Ensure the old URL is 404’d
To successfully redirect an old URL to a new URL the old URL must be 404’d. Otherwise, the redirect will not successfully be implemented.
3) Redirect old content to similar and relevant content
For example, say you have a product page that ranks really well for the keyword “black cropped leggings”. However, that product is being discontinued. To replace it, you have a newer version of the leggings that are being added to the site, which are almost identical to the old product. Implementing a 301 redirect from the old product page to the new one would be a great tactic to maintain search rankings and customers. On the other hand, say you decide to redirect the old product to a black jeans product page. This redirect would most likely not maintain traffic since the new page is not similar enough to the old one.
This is true with blog content, category pages, or any other type of page.
4) Add the new URL to the sitemap and remove the old URL
To speed up the crawling process, make sure you are removing the old URL from your sitemap and replacing it with the new one.
Keep in mind that even following all of the SEO best practices for redirects may not keep your page from losing some traffic. Oftentimes, when an old URL is moved to a new URL, it can take Google time to successfully crawl and rank the new URL. During this period, while you are waiting for Google to crawl the new URL, you may see some traffic losses.
Learn more about how to migrate site content while mitigating traffic loss: