Waaaay back in the days, I used Yahoo Site Explorer to check both my own inbound links and my competitor’s links. YSE has since shut down, but there are plenty of alternatives to Yahoo Site Explorer for backlinks that I like to use.
Tools to help find your competitor’s backlinks
Ahrefs – My personal favorite. The best link analysis tool in the industry. Their link database seems to be the largest, and the way you can cut the link data is extremely comprehensive.
SEMRush – SEMrush is a powerful and versatile competitive intelligence suite for online marketing, from SEO and PPC to social media and video advertising research.
SerpChecker – SERPChecker is a competitor analysis tool providing 49+ SEO metrics.
MajesticSEO – Link analysis tool that helps you understand the link profile of your own, as well as competitor websites and can empower the rational study of Search Engine positioning.
Link Research Tools – With its advanced proprietary technology, LRT is “all things links”. From building high-quality links to competitive link detox, this tool has it all.