Shoppers are no longer waiting for Black Friday to start to look for deals online, and many retailers are following suit by starting sales on Thanksgiving or earlier.

With Black Friday online sales expected to overtake Cyber Monday this year, online retailers capitalizing on that trend have been busy launching early previews of their holiday deals. Amazon.com Inc., No. 1 in the Internet Retailer 2017 Top 500, started its Black Friday sales Nov. 1, along with a number of other retailers. Black Friday refers to the Friday after Thanksgiving, while Cyber Monday refers to that following Monday. Both are traditionally two of the largest online shopping days of the year.

However, Black Friday itself will still see a number of unique deals rolling out online, with retailers offering matching in-store deals and offering unique discounts to draw in the masses of online shoppers. Market research firm Market Track found that 15% of people plan to do the majority of their holiday shopping on Black Friday alone, with another 12% getting the majority in across that long weekend.

“Although Black Friday was developed to encourage in-store shopping at the big box stores, it’s difficult for these big names to compete with the convenience of online [shopping], and forces them to make many of those deals available online,” says Dave Charest, director of content marketing at e-mail marketing firm Constant Contact.

Online sellers may want to get a jump start on publishing those holiday sales. Charest found that open rates for emails sent on Black Friday are actually lower than they are on Thanksgiving.

“The email open rate on Black Friday has dropped 11% over the last three years, despite a 20% increase in total emails sent in that same time frame, showing that consumers’ digital preference on that day is declining,” he says. “For the last three years, email open rates were higher on Thanksgiving than Black Friday. Far fewer emails are sent on Thanksgiving as companies may not want to bother their customers on the holiday.”

However, retailers concerned about bothering customers with early Black Friday emails don’t have to worry, especially if they’re sending messages late in the day. A survey from cash-back affiliate site Ebates found that 22% of respondents plan to shop online after wrapping up Thanksgiving dinner.

This year, many retailers are starting sales on Thursday afternoon. Department store chain Belk Inc. (No. 89) is starting sales at 4 p.m. both online and in stores on Thanksgiving and Toys R Us (No. 38) is launching online sales at 9 p.m., while Wal-Mart Stores Inc. (No. 3) is releasing its digital deals even earlier at 12:01 a.m. Online only sellers are also starting early. Jewelry retailer Blue Nile Inc. (No. 96), starts its deals on Thanksgiving at 3 p.m. and Amazon-owned Zappos sales starts at 9 p.m.

But not everyone is getting deals out before Black Friday begins. Both Wayfair Inc. (No. 16) and Target Corp. (No. 20) are starting deals in the morning. Still, those retailers have both offered various previews of sale items and early shopper deals as part of their Black Friday marketing.

And Black Friday is still a huge day for online shopping. A study from content performance marketing firm BrightEdge found that conversion rates are double the non-holiday sales season average on that day, along with Cyber Monday. However, BrightEdge senior vice president Kevin Bobowski says Thanksgiving sales will continues to grow.

“Our initial finding is that some of the traffic patterns and the retail activity is shifting toward Thanksgiving Day,” he says. “We believe that the traditional Black Friday of going to the stores and seeking out deals is just as easily accessible on Thanksgiving day.”

Tablets and desktops see higher conversion rates on Thanksgiving, while mobile conversions grow on Black Friday. He believes that people are making one or two holiday purchases of high-priced items on Thanksgiving using bigger screens, but making many more purchases with smaller order values on Black Friday through mobile devices.