Safari opens with 30 tabs automatically

1. Check your Safari Preferences > General. Make sure that "Safari Opens With" says "A new window." (Not "All windows from last session" or "All private windows from last session.")
2. In System Preferences (aka System Settings) > General make sure that "Close windows when quitting an app" is checked.

Further info here ->

• Control which windows Safari reopens on Mac - Apple Support
• Pin frequently visited websites in Safari on Mac - Apple Support

You could, of course, also erase all history before you close Safari each time (Safari > Clear History > Clear All History).

Have you tried removing all History? There are two ways to do it:

• Safari > Clear History > Clear All History > Clear History button
• On Safari menu strip - History > Clear History > Clear All History > Clear History button

Also, check Safari > Preferences > Advanced ... UNcheck Reading List - Save articles for offline reading automatically

is it possible that you have some "pinned tabs" in safari? if you drag the URL bar of an opened site to the left, it will "collapse" and create a "pinned tab". check your safari toolbar and see if there are web pages that only show the site's favicons.

if that is the issue, that is why those 30 pages open upon launching safari. you can drag the "pinned sites" to the right of the URL bar until they expand. then you close those sites as you normally would.

EDITED

CT wrote:

What happens if you launch Safari while pressing the shift key?

Heh heh ... it's supposed to prevent previously open browser windows from reopening when you launch Safari!

(I know, I know, you were asking the OP ... but I couldn't resist the rejoinder ... keep smiling!)

thank you MartinR for the Pin frequently visited websites in Safari on Mac - Apple Support link. I've added it to my list of links.

it does appear that those are NOT pinned tabs. have you tried MartinR's suggestions?

What happens if you launch Safari while pressing the shift key?