- HaYeo (Ha/Seul and Yeo/Jin)
- Both were born in South Korea.
- Both have brown eyes.
- Both have monolids.
- Both have brown hair.
- Both are part of the sub-unit LOONA 1/3.
- Both of them have had rapping and singing parts.
- YeoJin dorms with the members of ODD EYE CIRCLE, while HaSeul dorms with the members of LOONA 1/3.
- YeoJin is an only child while HaSeul has a younger brother.
- HaSeul is a good vocalist while YeoJin is a good dancer.
- YeoJin is part of the maknae line while HaSeul is not.
- HaSeul has promoted on music shows while YeoJin has not.
- HaSeul auditioned for MIXNINE and YeoJin did not.
- Although both are in LOONA 1/3, HaSeul had debuted in the sub-unit, whereas YeoJin is an non-promotional member.
- They are in the band LOONA.
- They are sisters in LOONA's webdrama Woomanna.
- Both were featured in the music video for Choerry's "Love Cherry Motion".
- There is a special section in "LOOΠΔ Kick Kick" called YeoSeulTV.
- YeoJin once got jealous when HaSeul complimented Choerry.