I told them at the hotel that I'd check-in by 11pm, but I think I might be late a little. I need to call them to let them know.
ホテルには11時までにチェックインと連絡してあるが、ちょっと遅れそう。電話入れておかないと。
does this sound natural?

The Language Level symbol shows a user's proficiency in the languages they're interested in. Setting your Language Level helps other users provide you with answers that aren't too complex or too simple.

• Beginner

  Has difficulty understanding even short answers in this language.

• Beginner-Intermediate

  Can ask simple questions and can understand simple answers.

• Intermediate

  Can ask all types of general questions and can understand longer answers.

• Advanced

  Can understand long, complex answers.