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CERTIFICATION

I, Steven Krause, certify that:

I have reviewed this annual report on Form 20-F of Pacific Rim
Mining Corp.;

1.      Based on my knowledge, this
report does not contain any untrue statement of a material fact or omit to state
a material fact necessary to make the statements made, in light of the
circumstances under which such statements were made, not misleading with respect
to the period covered by this report;

2.      Based on my knowledge, the
financial statements, and other financial information included in this annual
report, fairly present in all material respects the financial condition, results
of operations and cash flows of the issuer as of, and for, the periods presented
in this report;

3.     The issuers other certifying
officer(s) and I are responsible for establishing and maintaining disclosure
controls and procedures (as defined in Exchange Act Rules 13a-15(e) and
15d-15(e)) and internal control over financial reporting (as defined in Exchange
Act Rules 13a-15(f) and 15d-15(f)) for the issuer and have:

4.     
(a)      Designed such disclosure controls and
procedures, or caused such disclosure controls and procedures to be designed
under our supervision, to ensure that material information relating to the
issuer, including its consolidated subsidiaries, is made known to us by others
within those entities, particularly during the period in which this report is
being prepared;

(b)      Designed such internal control
over financial reporting, or caused such internal control over financial
reporting to be designed under our supervision, to provide reasonable assurance
regarding the reliability of financial reporting and the preparation of
financial statements for external purposes in accordance with generally accepted
accounting principles;

(c)      Evaluated the effectiveness
of the issuers disclosure controls and procedures and presented in this report
our conclusions about the effectiveness of the disclosure controls and
procedures, as of the end of the period covered by this report based on such
evaluation; and

(d)     
Disclosed in this report any change in the issuers internal control over
financial reporting that occurred during the period covered by the annual report
that has materially affected, or is reasonably likely to materially affect, the
issuers internal control over financial reporting; and

5.      The issuers other certifying
officer(s) and I have disclosed, based on our most recent evaluation of internal
control over financial reporting, to the issuers auditors and the audit
committee of the issuers board of directors (or persons performing the
equivalent functions):

(a)      All significant deficiencies and material
weaknesses in the design or operation of internal control over financial
reporting which are reasonably likely to adversely affect the issuers ability
to record, process, summarize and report financial information; and

(b)      Any fraud, whether or not
material, that involves management or other employees who have a significant
role in the issuers internal control over financial reporting.

|Date: July 23, 2012 | By: | Steven Krause        
|------------------- | --- | -----------------------
|                    |     | Steven Kraus           
|                    |     | Chief Financial Officer

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