Time travel

Time travel is the act of the player manually changing the time of their game to advance to a future event or go back to a past event without having to wait in real time.

Changing the time of date does not affect villagers, weeds, flowers, hair, trees, dump/recycling, mail, bell bank, turnips, police station/lost and found, or construction. It will, however, affect sun/moonlight season, weather, and the time until a holiday or event.

In
In, there are two options to adjust time and date - the Nintendo GameCube clock or the in-game clock access through the in-game options. The ideal option is to change the GameCube's internal clock, because the in-game clock affects the growth of trees, the way letters are sent, and how the Police Station and Dump restock with items. However, while the GameCube clock maxes out at December 31, 2099, the highest the in-game clock can go is December 31, 2030, after which time will reset back to January 1, 2030.

In
When changing the time in, players can select between two options. The first is the in-game method where players at the character select can click the phone and follow the option that goes to the Date and Time settings. The other is changing DS time. Depending on the DS model, the menu that allows you to adjust time and date will differ. The highest the players can time travel to is December 31, 2099, after which time will reset back to January 1, 2000.

In
As in, there are two options to change the date and time settings for. The easier option is to change the Wii date and time instead of the in-game date and time settings. This is again due to the in-game settings' affecting the bank interest, plants and trees. The highest time can go towards is December 31, 2035; once the Countdown commences, time loops back to January 1, 2000.

In
Changing the time and date setting in will require the player to tell Isabelle during the start-up screen "I need help first...". The highest the player can go for time travel is December 31, 2050, after which time will loop back to January 1, 2012.

In
is the first game in the series that does not have an in-game option to change the time. However, it is still possible to time travel by changing the Switch system time by disabling "Synchronize Clock via Internet" in order to adjust the time. The highest the Switch time and date options will go towards is December 31st, 2060, although it appears the game continues onward into 2061. However, recurring events, like the Bug-Off or Fishing Tourney cannot occur beyond 2060.

The effects of time travel are significantly lessened in this game. Villagers will no longer move out without notice after longer periods of time, now requiring permission to leave from the player. Weeds still occasionally spawn on the island, but weeds will no longer negatively impact environment rating unless the quantity of weeds on the island is above 100; in addition, Rafflesia no longer spawn for islands with the worst rating.

Events also have become harder to experience with time travel. This is due to many events being rolled up in updates and said events occasionally being time-locked such as Bunny Day, Nature Day, May Day, International Museum Day, Wedding Season, Turkey Day, Toy Day, and Festivale, a first in the series. Event can also be locked after being unlocked in a previous year, such as Bunny Day's dates of April 1–12, 2020 being disabled in the 1.9.0 Free Update in favor of the new dates of March 28–April 4, 2021. Events that are available in every year include the Bug-Off, Fishing Tourney, a player's or villager's birthday, and the Countdown, in addition to any events celebrated through the Able Sisters.

Effects of time traveling
There are advantages and disadvantages to time traveling. Below are the positive and negative effects on the game:

Positive

 * Allows the player to attend out-of-season events.
 * Allows the player to receive mail sooner.
 * Allows the player to receive bank interest.
 * New villagers move in sooner.
 * Fruit grow on trees sooner.
 * Different items available at all stores.
 * Ability to catch out-of-season fish and bugs.
 * Ability to obtain out-of-season DIY recipes.
 * Ability to gain facilities sooner (e.g., sewing machine, Shampoodle)
 * Speeding up the cooldown process after a villager requests to move out.
 * Infrastructure is built/demolished quicker (e.g., bridges, inclines, buildings).
 * In, time-traveling back to a previous Redd visit will re-roll his stock and re-allow the player to purchase art from him.

Negative

 * Villagers move away (unless done properly).
 * In, villagers will think of moving out, but no villager can leave without the player's permission.
 * Weeds spawn more rapidly (using Wisp by finding his lamp in and  can solve this; can be prevented in  by the Beautiful Town ordinance).
 * If too many weeds are spawned in, this could create a Rafflesia, dampening the Environment rating unless the weed is cleared up. This is not present in.
 * Flowers are shrivelled or missing (can be prevented in by the Beautiful Town ordinance; does not happen in ).
 * The player misses sales in GracieGrace, Able Sisters, Tom Nook's Store, Re-Tail, and Nook's Cranny.
 * The player's mailbox may fill, which disallows incoming mail until it is emptied (except in ).
 * The player gets bed head. In, this is merely temporarily and will allow the player to use bedhead as their hairstyle option.
 * Turnips rot.
 * Turnip prices will reset if time traveling backwards in.
 * Phineas is gone for a while.
 * As of version 1.9.0 in, traveling back in time five days or more resets the visiting special characters for the target week. In previous versions, this limit was only in place if the target and present date were in different months.

Other effects

 * Flowers may end up overpopulating the island by either duplicating or breeding in if nothing is done to prevent flowers from spawning in grass/dirt tiles.
 * NPC visitors will take up seven slots within a week after the day moves from Sunday and Monday, and moving between each specific day will initiate that specific visitor (e.g., Leif will always be present on Tuesday unless the day moves to another Monday)
 * Villagers start referring to the player as a 'time traveler'