Exhibit 10.1

THIRD AMENDMENT TO THE
ST. JOE COMPANY SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN

(As Amended and Restated Effective January 1, 2002)

Pursuant to Section 9.1 of The St. Joe Company Supplemental Executive Retirement
Plan (As Amended and Restated Effective January 1, 2002) (hereinafter the
“Plan”), said Plan is hereby amended effective January 1, 2005, as follows:

1. Section 2.4 of the Plan is amended and restated in its entirety to read as
follows:

“2.4 ‘Annuity Starting Date’

Means the dates as of which a lump sum distribution is made to a Participant or
Beneficiary.”

2.   Section 4.3(a) of the Plan is amended and restated in its entirety to read
as follows:

“(a) A Participant’s Account shall be credited with Interest for the Plan Year.
Interest shall be credited (except as hereinafter provided) on the last day of
the Plan Year and shall be determined by multiplying the balance in the
Participant’s Account as of the first day of the Plan Year by the Applicable
Interest Rate for the Plan Year. If the Participant’s Annuity Starting Date
occurs in a Plan Year, Interest shall be credited as of the Participant’s
Annuity Starting Date by prorating the otherwise Applicable Interest Rate based
upon the number of complete calendar months which have elapsed from the
beginning of the Plan Year to the Participant’s Annuity Starting Date.”

3.   Section 6.1 of the Plan is amended and restated in its entirety to read as
follows:

“6.1 Payment upon Termination of Service

If the service of a Participant with the Employer shall be terminated for any
reason other than death, such Participant’s vested Account shall be paid to him
by the Employer. Payment of such benefits shall be made on the later of
December 31 or six (6) months following such termination. The amount of any lump
sum distribution shall be based on the value of the Participant’s vested Account
as of the last day of the month immediately preceding the payment date.”

4.   Section 6.3 of the Plan is amended and restated in its entirety to read as
follows:

“6.3 Mode of Payment
Except in the case of a Participant who began receiving a distribution of his
account in installments beginning in the 2005 Plan year or earlier, any vested
Account payable under the Plan shall be paid as a lump sum.”

5.   Section 6.4 of the Plan is hereby eliminated.

6.   New Section 9.3 is hereby added to the Plan as follows:

“9.3 Compliance with Code Section 409A
Notwithstanding the provisions of Section 9.1 and 9.2 above, no such amendment
or termination shall be permitted if it would result in the imposition of the
additional 20% tax on a Participant’s accrued benefit as of the date of such
action as provided in Code Section 409A and the regulations and guidance issued
thereunder, or would otherwise adversely affect a Participant’s accrued benefit
as of the date of such action.”

IN WITNESS WHEREOF, The St. Joe Company has caused this Amendment to be
executed, effective as of the date first set forth above, by its duly authorized
officer.

THE ST. JOE COMPANY

     
Dated: September 18, 2006
  By: /s/ Jay Romans
 
   
 
  Jay Romans
Senior Vice President, Human Resources