Source for information – How to Switch from Yahoo! Mail to Gmail (with Pictures) – wikiHow.
I found and tested this out myself. Using a Yahoo mail account I have had since 1998, I went into Gmail and used the Gmail options to transfer all my old email from the Yahoo account into Gmail.
On the con side… it did import a massive amount of spam email from Yahoo.
This was AFTER I had deleted every last spam in the account. However, it took a few days for the import and during that time yet more spam gathered. So not only did I get the old email I wanted but also all the latest junk I could have happily done without.
On the pro/ plus side… it worked!!!
I tried to find a way to import old email from Yahoo a couple of years ago. Yahoo had blocked any options (unless you paid for a premium account with them). I didn’t want a paid account when all I wanted was my existing email. I have not used that account in quite a bit longer than ten years. So, paying for it seemed nonsense. (Especially due to the more than average amount of junk/ spam which flooded in to an account inactive for son long).
Gmail let me know when the Yahoo transfer was complete. There was a note at the top of my Gmail account, highlighted in yellow. Everything imported over was labelled with the Yahoo email address. That made it easy to find. At first I thought all I had was the spam. There were 6,000+ imported emails. I had cleaned the account and left about 300 emails to be imported over. I had to dig and scroll to find the email I wanted to keep. Luckily, Gmail lets you select unread emails. I used that feature to select and delete the junk. This left the older emails alone.
So, you can save old email from Yahoo Mail and not have to pay for it. Next I’m getting my Mother to do the same. One thing you do need to do – pull all your emails into the InBox and out of all folders. Anything in folders will not be imported (according to the directions in the post on WikiHow).
Note: Not everything was exactly as WikiHow reported it. Maybe the procedure was updated since that article was posted. It was actually simpler and if you follow along with the instructions in the pop-up window from Gmail you will do fine.