The best replacement for mandolin is ukulele.

The best alternatives to mandolin are rated as following:
★★★★★  ukulele
★★★★  banjo
★★★★  guitar
★★  violin
★★  mandola
★★  bouzouki
★  fiddle
★  food processor
★  mandoline
★  spiralizer
★  julienne peeler
★  lute
★  spiral slicer
★  banjo easier
★  octave mandolin
★  dulcimer
★  mandolin
★  guitar easier
  ukulele which is easier
  uke
  ukulele tuning
  ukulele learn
  v-slicer
  guitar learning
  f style mandolin
  tenor banjo

Your alternative for mandolin is not listed? Suggest!
Speaking about mandolin, one probably shouldn't forget about waffle cut.

Other search terms related to mandolin and their ratings are:
★★★★★ waffle cut
★★★★ julienne
You have in mind a companion for mandolin and it is not yet here? Propose!



Google Trends

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mandolin
ukulele
banjo