Join with vs.Join up vs. Join up with vs Join in with

Join with something in doing something

To get involved in an activity or journey with another person or group:

- The design company is planning to join up with a shoe manufacturer and create a new range of footwear.
- The police have joined with (= They have begun to work with) the drugs squad in trying to catch major drug traffickers.
- Parents have joined with health experts to produce a video for bereaved families.

Join up
1-To become a member of one of the armed forces:

- I joined up when the war broke out.
- He joined up at eighteen and after two years he went abroad.

In British version it means to connect things, or to become connected:

- I used to join up all his paper clips in a long chain.

2-to meet or work with someone else:

- I'm going to Germany first, but we're planning to join up in Norway.
- They decided to join up later because of some disagreements.

3- to work together to achieve something:

- We're joining up with another research team.

Join up with
1-To combine with or meet other people in order to do something:

- Three months ago, they joined up with another big company that sells arms.
- The other students joined up with us to continue the project.


Join someone in doing something
to take part in an activity with other people .

- They joined him in singing.
- They joined me in taking a long trip to the North.
- At the end of the his speech, they joined us in thanking Mr Smith for his help.

Join in with
To participate in an activity with other people with a certain work.

- We joined them in the chorus with singing.

Join someone for

- We joined him for lunch/drink.