Home → Irregular verbs → swim
Past tense of “swim”
🏊 To move through water using your body.
Number 59 of 175 by frequency, well inside the everyday core, and the vowel walks i → a → u. Worth learning properly rather than recognising vaguely.
Mistakes people make with “swim”
Not “swimmed”. Swim does not take -ed — the past simple is swam, however regular it feels to add the ending.
Not “have swam”. After have, has or had the verb switches to its third form: I have swum, never I have swam. This one survives into quite advanced English, so it is worth over-learning.
Phrases you will actually hear
These are worth learning whole. A verb sticks far better inside a phrase somebody would really say than on its own in a table.
The vowel walks i → a → u
Only one letter is doing the work. swim becomes swam becomes swum, and everything around the vowel stays where it is.
Say the three aloud and you can hear the staircase: i → a → u. This is the oldest verb pattern in the language, inherited from Germanic, and it is the one group where guessing actually works — meet a new verb of this shape and you can usually predict its forms.
The mistake to avoid is stopping halfway: I have swam instead of I have swum. The u form belongs after have.
- Past simple: We swam in the lake yesterday.
- Past participle: She has never swum in the sea.
The same pattern — i → a → u — runs through 8 verbs:
Practise it
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