Mario Day (also written as Mar10 Day) is an annual celebration of the entire Mario franchise. It takes place on March 10th each year, the reason being that this date, written as "Mar10", looks like Mario's name. The holiday could be celebrated by dressing up as Mario, having a Mario-themed party, or simply playing Mario games, among others. Although the holiday was not created nor declared by Nintendo, the day was unofficially celebrated by most Mario fans. Since 2016, Nintendo has officially embraced the holiday and started celebrating annually by promoting Mario games and holding Mario-themed events. On an American Broadcasting Company news broadcast on March 10, 2017, the headline "National Mario Day" was played celebrating Mario Day where the reporter talked about Mario Day, its name and Mario.
In 2016, Nintendo celebrated the holiday by releasing a video on their official YouTube channel titled "Celebrate Mar. 10 - Mario Day!". The video is about a person in a Mario costume walking around Nintendo's office turning things into Mario-related objects such as turning notepads into Nintendo 3DS systems. The person also adds Mario-related stuff to the office such as several Mario plushies to a person's desk.
In 2017, Nintendo celebrated the holiday by adding a free Mario-themed frame to Facebook and the Messenger Camera that could be used from March 10 at 5 a.m. PT until March 12 at 11:59 p.m. PT., by putting several Mario games on sale on Amazon, and by having several My Nintendo rewards for Mario titles such as a 30 percent off discount on Mario Kart 8. They also worked with the Starlight Children’s Foundation by providing new designs for their gowns while making a donation to create 2,000 gowns. There was also a browser game released this year on the Play Nintendo website called MAR10 Day 2017 - Mario Quiz.
In 2018, Nintendo partnered with Google adding Mario in Google Maps, where the user can have Mario drive around in a Pipe Frame. Users had to look for a ? Block next to the start button when the start and destination fields were filled. Nintendo also held an in-game event in Super Mario Run, called "It's All About Mario Event", where all Mario-related items are in fixed appearance rates in Super Bonus Game. At the same time, Nintendo offered a special 50% discount for the full game. Several rewards for My Nintendo include the "Mario's Mighty Mustache" 3DS theme.
In 2019, Nintendo released a promotion in Europe where buyers who purchased Super Mario Odyssey, New Super Mario Bros. U Deluxe, Mario Kart 8 Deluxe, Super Mario Party, or Mario Tennis Aces between the 8th and 10th of March would receive double Gold Points. In North America Nintendo released several My Nintendo discounts on Mario games, discounted download codes for the games that where included in the My Nintendo promotion in Europe to cost $39.99 from participating retailers, and discounted Nintendo Switch systems with one of five select Mario game to cost $329.98.
Nintendo also released an episode of Nintendo Minute on their official YouTube channel titled "Mar10 Day Character Bracket: Mario’s Enemies - Nintendo Minute". In this video, series' hosts Kit and Krysta rank several Mario enemies based on several categories, such as which would be the most annoying pet. Nintendo of America made a celebratory tweet for the holiday asking how fans will celebrate Mar10 Day. There were also several Mario-related activities that took place at the Nintendo New York store, which were sponsored by Frito-Lay Variety Packs.
The event "It's All About Mario Event" returned in Super Mario Run, and the player were given 10 Rally Tickets as a log-in bonus. In Animal Crossing: Pocket Camp, Mario's hat and outfit were gifted for all players, and several Mario-themed wallpaper and flooring were available for crafting. Several of the furniture from the prior Mario-related event returned, and the Fishing Tourney 12 for the game featured Cheep Cheeps, Eep Cheeps, Cheep Chomps, and Bloopers as catchable fish.
The Mario Bros. Tour in Mario Kart Tour featured Mario and Luigi wearing their Donkey Kong and Super Mario Bros. The Lost Levels outfits, respectively, and ran until the actual Mario Day. Select Mario games had a $20 discount in the US eShop resulting in $39.99 from March 8, 2020 (9:00 a.m. PT) to March 14, 2020 (11:59 p.m. PT), them being Super Mario Maker 2, Super Mario Party, Mario & Sonic at the Tokyo 2020 Olympic Games, and Yoshi's Crafted World. Lego and Nintendo released short videos on their Twitter accounts, teasing a Lego and Mario crossover, which was eventually announced as LEGO Super Mario. Unlike in 2017 and 2018, there was no Mario crossover event with Animal Crossing: Pocket Camp, largely due to their doing an event focusing on the then-impending release of Animal Crossing: New Horizons.