I recommend reading, reading, reading. Then for grammar, I like Loyola Press's Exercises in English since it is very thorough and succinct:

http://www.rainbowresource.com/searchspring.php?q=loyola+press#/?_=1&page=1&filter.category_name=English%2FWriting%3E%3EGRAMMAR%20SKILLS%20(GRAMMAR%2FUSAGE%2FMECHANICS)

Then there is Royal FireWorks Press, Michael Clay Thompson's books which are a pleasure and cover grammar, vocabulary, and writing:

http://www.rfwp.com/pages/michael-clay-thompson/

A good alternative for vocab is Sadlier Oxford's Vocabulary Workshop:

http://www.sadlier-oxford.com/vocabulary/

Thank you everyone who took time to respond. I am just now back online after a few days so will look the resources up!

One completely free resource for your younger kids, if you don't mind working on computers or printing things out, is the Core Knowledge Language Arts program: http://www.coreknowledge.org/ckla

This could help keep up their English vocab for science and other subjects, too.

No Red Ink for on-line.

Daily Grams are workbooks we have used that are quick and easy; they would just do one page a day after school.

I think that's great OP that you're doing this. I know so many people who grew up speaking another language at home who can't read/write in that language, so kids definitely could lose those skills if you don't keep them up.

Calvert curriculum.

Honestly, for the older ones, I'd concentrate on bringing pleasure reading books they can enjoy. They are going to have s difficult time reading for pleasure in the new language. The first grader is trickier and depends on how well your child is reading in Enlish before leaving.

Hello

our family is moving overseas and our kids will be going to the local schools, in local language (currently they go to regular school here). I was told by expats there to look into homeschooling resources to keep their English at grade level, I would work with them over the weekends or whenever we can.

Can you could please recommend books to buy and take with us, and/or online resources that would be great. I want to focus specifically on English as a language since they willb e getting the other academics like math, science etc in school

Kids are rising 7th grader, and rising 4th and 1st graders

Thank you so much!