will sneakers be OK for hiking in Cinque Terre?

It depends on how much support the shoe offers. I'm not familiar with the brand but if it is an athletic type shoe I think you will be ok. When we were there my wife and I wore our sneakers. She wore Pumas and I wore Sketchers. I got blisters and she was fine. Her shoe had more athletic type support than mine.

I understand trying to avoid packing little used items. We hiked the entire trail last May and I wore my hiking shoes. My husband wore his Keen sandals. I think your sneakers will be fine. Are you planning to do other hikes during your trip? I took my boots because we also hiked in the Amalfi coast area and in the Lake Como region. I wouldn't mail your boots, especially just for this trail. We saw all kinds of shoes on the trails in CT, anything from full gear with poles (mostly Germans and Dutch) to flip-flops.
Have a wonderful trip.

What do you wear when hiking at home? On the CT trails I've seen everything from flip-flops to serious hiking boots. I wear a sturdy walking shoe. The CT trails range from easy and mostly level (the southern two legs) to very hilly with lots of ups and downs. Go for a couple of challenging hikes at home in your sneakers and see how that works. Then you will know.

Thanks Everyone! I think my sneakers will do it. They have a good heavy sole. I used a similar pair to hike a small mountain in New Hampshire last summer and I was fine. Sore knees after, but it sounds like the CT trails are not as steep.
Grazie!

Good sneakers will be fine if the weather's dry. It's not so much the steepness of the trail itself as the fact that parts of it are very narrow running along a steep slope. You really, really don't want to slip. (I remember at one point having to step out onto a horizontally growing tree to let some other people pass.)

Mary, Sneakers will be fine with one exception, if the weather is wet. Most of the hiking is not dangerous unless it is wet, and then there are places that you will need to be really careful.
Most of all, ENJOY!. Jeff
P.S. Try the local Vernazzan dishes, and most importantly buy a bottle of Sciachettra(SP) and take it to the breakwater with your husband late at night. you will never forget it! Caio, Jeff

Your Saucony shoes will be fine. I am a very avid hiker and did the Vernazza to Corniglia section last summer. I and a lot of other people have moved from boots to trail running shoes just about any any kind of hiking these days. In fact, mine are Saucony's too. I am not sure if your Saucony's are for "trail running", but they should be ok.

Running shoes are fine but if it has rained or is raining while you're on the trail, it can be very slippery! This is especially true on the section from Vernazza to Corniglia. Another important point, take your time and soak up the views!! Enjoy!

Hiking boots are not necessary for the main CT trails from Monterosso to Riomaggiore. I hike the entire route in July with my New Balance 1222's. No issues at all, but if the trails were wet and slipperly, that could be a different story.