This guide contains the following information.

Support thresholds in Three Houses are implemented in a very similar manner to previous Fire Emblem games. Once the support points between two characters reach a certain value, they will unlock a support conversation along with the next support level. Three Houses adds another mechanic to this, where there can be (C+, B+, A+) supports along with the usual (C, B, A) supports. This varies based on unit pair, and will be indicated in game by a little arrow marker above the affected support level.

Once you have reached a threshold and unlocked a support conversation, it is important to view the support conversation as soon as possible. Units who have a pending support conversation will not gain any support points until their conversation has been viewed. The following table shows the support point thresholds for each support level.

Most of the group activities around the monastery will build support with all the units involved. Because of this, Byleth will build support with other characters the fastest. This is convenient because Byleth can support every playable character in the game (except for Anna). Click the button below to see all activites together in a table.

All support-boosting activites are listed below, click them for details.

The amount of support gained from sharing a meal depends on whether or not the two invitees like/dislike the meal. Head over to the Dining Hall guide for more information on that. If the two characters you picked can support eachother, they will also gain support points. All characters involved in the meal share will gain the same amount of points, so it's in everyone's best interest to pick units that actually enjoy the food. Furthermore, some days will have special events that boost the effects of sharing a meal for certain units. The gains are doubled for all affected units.

The support gains are halved rounded down when eating the daily special (which does not cost any ingredients). This includes daily specials eaten during dining hall events, effectively cancelling out the bonus.

All combinations of like/dislike along with their support gains are listed below.

The amount of support points gained between Byleth and the character they cook with depends on that character's cooking prowess. Again, the Dining Hall guide has more information on that. The support gains for each prowess level are listed below.

Byleth can give characters gifts when interacting with them around the monastery, or after a good teatime. The amount of points gained are determined based on how much the character likes the gift. A list of liked and disliked gifts are shown on any individual character's page. All Church of Seiros faculty members receive a 45% boost to support points gained by gifts. This information is detailed below.

Giving birthday flowers will give 5 support points.

Returning a lost item will give 20 support points. Faculty members do not receive the same 45% bonus as they would from gifts. Again, a list of all lost items can be found on any individual character's page.

Support gains from teatime depend on how many impactful conversations you had. This is indicated by the game telling you whether you had a "Perfect", "Great", "Nice", or "Failure" teatime. Use the Teatime Assistant to always get perfect teatimes. Giving gifts at the end of teatime does not have any bonus effects compared to giving gifts normally. There is a more detailed explanation of the teatime mechanics in the Teatime guide.

Every explore phase, Byleth can participate in choire practice with two students. Oddly enough, it does not matter how much the participants enjoy singing, everyone involved will always receive 30 points.

Occasionally, there will also be events that involve hymns (Saint birthdays, etc.), where the same choir practice animation is shown for Byleth and two random students. From my own testing, this appears to either give the same 30 points, or a little bit more. If you know the exact value for this, contact me.

Byleth usually has some options on what to say when talking to characters around the monastery. Occasionally there is an option that the character likes, and rarely there will be an option that the character doesn't like. This also happens during cutscenes and some support conversations.

You will get 5 points for an option that the character likes, and you will lose 5 points for an option that the character doesn't like.

Viewing a support conversation will also earn some points, depending on the level of support. Keep in mind that you cannot earn further points until you view an available support conversation.

You can earn support in battle by having your deployed units fight nearby eachother. Adjutants will also gain support with the unit that they are assigned to. Byleth will gain less support with other units during battle, this is likely to compensate for all of the monastery support building. The following sections list the support gained from battling, as well as the support gained from adjutants.

The following table lists all battle interactions between deployed units that can build support. Of course, only units who can build support will gain these points.

At the end of the battle, all viable support pairs amongst the deployed units will gain 2 points. Byleth will gain 1 point with all other deployed units. Non-combat gambits, and spells like Fortify and Restore do not build support.

Mission assistance units will always gain support with Byleth when doing any of the above, even if Byleth is not adjacent or involved at all.

Adjutants will gain support with their assigned unit when they perform actions in battle. There is no support earned for Adjutant Follow Up, Guard, or Heal when they activate. The following table lists all of the actions performed by the deployed unit that will build support between the adjutant.