There is a menu that lists all the expeditions available to the player and displays their associated locations on a map. By selecting an expedition, the player can choose which Pikmin to assign to that expedition, and then those Pikmin will walk to that expedition's associated location, collect the item, and then walk back to the player. This takes some amount of time, and the approximate time it will take is told to the player before the expedition is started. Pikmin on expeditions cannot be used for other purposes while they are on the expedition.
There is a chance for Pikmin on an expedition to return with a postcard. This postcard can be collected alongside the fruit or seedling the Pikmin was carrying, and will be shown on the screen, temporarily interrupting gameplay. The postcard will be an image of the area the Pikmin collected the fruit or seedling from, and it will show them posing in that location.
If a Pikmin is at max friendship level, an expedition to a gift box will appear. Only the Pikmin who is at max friendship can complete this expedition, and the gift box in question will be located where the Pikmin's seedling was discovered. When this expedition is completed and the gift collected, the Pikmin will jump into the gift box and come out as a Decor Pikmin.
Different items collectable on expeditions have different carrying weights and thus take a different number of Pikmin to carry. Red Pikmin, Yellow Pikmin, Blue Pikmin, White Pikmin, and Winged Pikmin can carry 1 weight unit. Rock Pikmin can carry 3 weight units. Purple Pikmin can carry 5 weight units. Below is a table of the weight of each collectable item (in weight units) and the maximum number of Pikmin that can carry it (as a number of Pikmin).
The length of time an expedition takes depends on the Pikmin that are sent on it. Generally, the more Pikmin are sent, the faster the expedition will be. However, different Pikmin types have different traits, and mixing them can produce different results. For instance, Winged Pikmin are the fastest out of the five types, but selecting any other Pikmin type to go along with them will greatly increase the length of the expedition. Speed is only influenced by the type of Pikmin, not its maturity or friendship.
An expedition has 2 stages. First, the Pikmin run from the player's starting location to the location of the expedition. Then, they pick the item up and carry it back to the player. These stages take different lengths of time. The time it takes for the Pikmin to carry the item back also depends on the player's movement, as the expedition will not be over until the Pikmin reach the player's current location. If the player moves away from the expedition, it will take more time, and if they move towards it, it will take less time. This can make the time estimate from the beginning of the expedition inaccurate.
In the running stage, each type of Pikmin has a set speed it runs at, and the speed of the group isn't affected by the number of Pikmin sent. Red Pikmin, Yellow Pikmin, and Blue Pikmin run at 4 meters per second (m/s). White Pikmin run at 8m/s. Winged Pikmin run at 20m/s. Purple Pikmin and Rock Pikmin run at just over 3m/s. It is not yet known how running speed works when multiple Pikmin types are sent on the same expedition.
In the carrying stage, the speed is affected by how many Pikmin are carrying the object. Each Pikmin added to the group increases the speed by some amount, and that amount depends on the type of Pikmin and the weight of the object. Each type has some value which is divided by the weight of the object to get the speed increment. For Red Pikmin, Yellow Pikmin, and Blue Pikmin (the main types), this value is 1, so adding one to the group will increase the speed (in meters per second) by 1 divided by the weight of the object. For fruits, which have a weight of 6, this increment will be 1/6 for these three types. For White Pikmin and Rock Pikmin, this value is 2, so they carry twice as fast as the main types. For Winged Pikmin, this value is 5. For Purple Pikmin, this value is 4. The increased carrying strength of Purple Pikmin and Rock Pikmin appears to have no effect on the speed, as these types add a speed increment for each Pikmin in the same way the other types do. It is not yet known how carrying speed works when multiple Pikmin types are sent on the same expedition.