Swim into (something) phrase
To go from one body of water to another by swimming.
I saw a shoal of herring swim into that crevice.
He jumped off the bridge and swam into the dark hole under it.
To swim against the flow of some force, such as a tide, current, wave, etc.
To make exercise more strenuous, you can go to the sea and swim into the current.
I had to swim into the current to get back to the shore.
The verb "swim" must be conjugated according to its tense.
The origin of this phrase is not clear.