When should hyperlinks be underlined?

Summary: Textual links should be colored and underlined to achieve the best perceived affordance of clickability, though there are a few exceptions to these guidelines.

1. Why are some hyperlinks underlined?
2. Should hyperlinks be underlined in print?
3. Should hyperlinks always be blue?
4. Should links be underlined on mobile?

Why are some hyperlinks underlined?

Links are easy to find because users understand that underlined text means that it's a link. The underlining draws their attention.

Should hyperlinks be underlined in print?

In a later blog post, however, APA clarified that blue and underlined hyperlinks should be avoided in documents intended to be read on paper. When printed, the blue becomes grey, the underlining impedes readability, and obviously the links are of no use anyway.

Should hyperlinks always be blue?

Some shade of blue is good, not necessary the default one. For desktop clients, adding underline on hover is nice and makes the color less important, but for mobile clients you need to convey that the link is clickable without any user interaction before.

Should links be underlined on mobile?

Not To Underline

Studies have shown that using underlines should be avoided; this is more apparent when the content shown is comprehensible and easily recognisable. For example, if you have a list of many links, each one being underlined could confuse the user and potentially hinder what they want to find quickly.