Probably depends on what you use your island for. Do you use the island to eat regular meals or strictly for cooking, prep & a catch-all space. If the latter, then it might work fine.

Our island is 6.6' x 3 feet. We generally eat all of our meals there. Now, as we're replacing countertops, we're eliminating the prep sink. We found we never used the sink, just one more thing to clean & it really broke up the continuous area of open counter for work space, spreading out the newspaper to read, etc. If we find we miss the sink, we'll add it back in.

How many cooks do you have in the household? I always thought I wanted the second sink, but I'm the only one who ever cooks so there really wasn't a need for the second sink except for maybe once a year when we entertained large groups & someone was helping (ie Christmas, graduation).

we were going to put a prep sink in the island but then we were adviced that we probably wouldn't use it that much and the island would look nicer without it. also, how close is your main sink to the island? ours is very close so the reduncancy seemed unneccesary. plus we are a one cook household.......

A 12"x9" sink probably isn't worth giving up island real estate. That size sink isn't very useful since it's too narrow to work in. If you can, visit plumbing or big box stores to find one to see how it feels. If not, try to find or mock up a box of those dimensions and see how it feels/works.

When we were considering a 10" wide sink our KD told us anything less than 12" in both directions is not very useful. Ours is 15-3/4" x 15-3/4" and, personally, I think it's just big enough to be useful. I'm not sure even 12" would be useful! Just my opinion, of course!

My island is slightly bigger than 3ft by 4 ft and I love my prep sink! It is 13x16 inches, and is the smallest I could live with. the island is mostly for prepping and laying out foods, although the kids eat some meals there. There is room for 2 stools. I use this sink more than the main sink, I also have a garbage disposal attached.

A lot depends on the location of other things in relation to the island. I agree that if you do it, the sink needs to be bigger to be of much use.

I agree that if you do it, the sink needs to be bigger to be of much use.

Our pre-remodel prep sink was 10" by 10" (inside bowl dimensions) and we found even that size to be quite useful. We did most of our produce washing in it. It was big enough to hold a colander for draining pasta or for draining veggies after washing or a bowl for soaking some produce that needed it - but not at the same time. It was big enough for washing hands too or for rinsing chicken off before preparing it.

Definitely a bit bigger would be more comfortable to use - especially if you want to do two things at once - or if you want to put a really large pot in it to fill - or you can have a pull out faucet and can use that to fill a pot sitting on the counter next to the sink.

We used the little one so much that when we remodeled we put in a much bigger one - the same size as the larger bowl on our main sink.

Whether yours is a multi-cook kitchen and how conveniently located the kitchen sink is for food prep vs the island would be things to consider. And 9 by 12 or 10 by 10 like we had would be compromises - a 15 by 15 or 13 by 18 would be nicer to use.

...maybe this has some bearing....how big are your hands? :-)

Seriously, I have big hands (wide & long fingers) to go w/my 5'10" body (I wear Men's Large gloves since Women's L are too small & short!) My husband is 6'5" and has proportionately bigger hands....so maybe that's why I think my sink is smallest I would go with...so, YMMV!

(I do think, however, that you should go w/at least a 12"x12" or 12" round sink.)

I think my sink is a 12" round (might be 10...I'll measure for you tomorrow). It's in our 43"x33" island and we planned it carefully. It has a disposal (A must) and is on the opposite side of the stove so I can use it for prep of vegis and salad and it can be used for hand washing so the kid/s are not in DH's work zone.

I don't have a good pic (I just tried to find one). I'll take one tomorrow to show you. There's still good space on each side to stack plates or some such and to stack and work on vegis. The stove side is basically clear, which makes it usable for the other cook as well.

I bought a 12x9 and didn't like the shape in the island. The round is more functional for all of the reason's above, but particular for splash issues since you can go a bit bigger sometimes.