AMARIN CORP PLC\UK — Director's Dealing 2012

Jul 30, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AMARIN CORP PLC\UK (AMRN)
CIK: 0000897448
Period of Report: 2012-07-26

Reporting Person: Zakrzewski Joseph S (Director, Chief Executive Officer)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-07-26	Ordinary Shares	A	33333	—	Acquired	111937	Direct
2012-07-27	Ordinary Shares	M	150000	$1.35	Acquired	261937	Direct
2012-07-27	Ordinary Shares	S	71946	$14.58	Disposed	189991	Direct
2012-07-27	Ordinary Shares	S	78054	$14.07	Disposed	111937	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-07-26	Restricted Stock Units	$0	A	33333	Acquired		Ordinary Shares (33333)	Direct
2012-07-27	Stock Option (right to buy)	$1.35	M	150000	Disposed	2019-12-21	Ordinary Shares (150000)	Direct

Footnotes

F1: The Ordinary Shares may be represented by American Depositary Shares, each of which currently represents one Ordinary Share.

F2: On February 1, 2012, the Reporting Person was granted 200,000 restricted stock units (the "RSUs") under the Amarin Corporation plc 2011 Stock Incentive Plan. Each RSU represents a contingent right to receive one Ordinary Share or cash in lieu thereof at the Issuer's discretion. The RSUs vest in six equal installments based on the Issuer's satisfaction of certain performance criteria and continued employment of the Reporting Person as provided in the Restricted Stock Unit Award Agreement between the Issuer and the Reporting Person. The performance criteria for the first installment was met, resulting in vesting of 33,333 RSUs.

F3: These RSUs vest on July 26, 2013, subject to continued employment of the Reporting Person through such date. Ordinary Shares will be delivered to the Reporting Person as soon as practicable after the vesting date.

F4: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 9, 2012.

F5: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.32 to $14.33, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F6: On December 21, 2009, the Reporting Person was granted an option to purchase 1,170,000 ordinary shares under the Amarin Corporation plc 2002 Stock Option Plan. The stock option initally vested in four equal annual installments beginning on January 1, 2010. In December 2010, the Issuer's Board of Directors approved the acceleration of the vesting of this award by six months such that the option vested in four equal installments and became fully vested on July 1, 2012.

F7: Each RSU represents a contingent right to receive one Ordinary Share or cash in lieu thereof at the Issuer's discretion.

F8: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $14.32 to $13.54, inclusive.