What to Expect - Important Dates and Information

 As we prepare for you to join the First Financial family, our goal is to make the transition as seamless as possible. 

Personal and Business Debit Cards


If you currently have a MainSource personal or business debit card, your card will continue to remain active until Tuesday, May 29. Please look for your new First Financial debit card with detailed instructions prior to May 25.


Activation Details

-Your First Financial debit card will begin working on Tuesday, May 29.

-Your new card must be activated before it can be used. Remember, it cannot be activated or used until Tuesday, May 29.

-Upon activation, you will be prompted to select your PIN.

-Don’t forget to change your card information for any automatic payments or accounts tied to your debit card after it is activated on May 29.


Didn’t receive your debit card?

If you do not receive your new debit card by Friday, May 25, please call 877.322.9530 and our team will be able to assist you in ordering a new card. You will also be able to visit any First Financial Bank on May 29 to get a card instantly issued.




Health Savings

Online Banking FAQ's

Need directions for first time login? Looking to learn more about new features available to you or your business within online banking?

Find out the answers to these and other online banking questions.


Treasury Management Clients
5 Things To Know About
Cash Management Online Banking


1. Navigation & Functionality: Navigation and functionality will be similar to your current MainSource online banking experience; however, you will notice a new branded look and some enhanced capabilities.

2. Availability: MainSource online and mobile banking will not be accessible after 6:00 PM EDT on Friday, May 25, 2018. You can begin accessing your account(s) through First Financial online and mobile banking any time after 8:00 AM EDT on Tuesday, May 29, 2018.

3. Logging In: Please continue to use your current Customer ID, User Name and Password.

4. Dual Control: Dual Control is a default setting within Cash Management Online Banking. You may choose to opt out via the Security Procedures Supplement.

5. Fraud Control: Positive Pay will be available to your business. This enhancement includes teller positive pay and ACH positive pay.


Please contact our First Financial Business Service Center at 866.604.7946.


Please refer to the guides below for questions regarding the transition of your account(s).

Personal & Non-Cash Management Business Clients

Through Friday, May 25, 2018, you may continue contacting the MainSource Bank Customer Service Center at 800.713.6083. Beginning Saturday, May 26, 2018, please contact the First Financial Bank Client Service Center at 877.322.9530 or stop by one of our convenient banking centers.

Cash Management Business Clients

Please contact our First Financial Business Service Center at 866.604.7946.

Coming Soon – More Locations to Serve You

We’re excited to announce our expanded footprint to serve you! On Tuesday, May 29th, you will now have access to more than 150 banking centers in Ohio, Indiana, Illinois and Kentucky. MainSource banking centers will reopen on the morning of May 29th with a new refreshed look. Stop-in and see us!

In certain areas, First Financial and MainSource have banking centers that are in close proximity to each other. After careful consideration and evaluation of several factors, a decision was made to consolidate certain banking centers. To review the affected banking centers and new addresses, click the button below.


Routing Number Update - On May 29

First Financial Bank will continue to honor existing checks and transactions under the MainSource Bank routing number post conversion. Although not required, we highly encourage you to notify your employer or anyone else presently making direct deposits to your account as well as any individual or company currently deducting automatic payments from your account of this change.

The First Financial routing number is 042200910. Do not update your routing number prior to Tuesday, May 29.

Some clients may have received notification of an account number change. In this case, please defer to the instructions in the communication for updating your routing number and ordering new checks.