Document and Entity Information	Total
Prospectus:
Document Type	485BPOS
Document Period End Date	Mar. 31, 2023
Entity Registrant Name	MFS® MUNICIPAL SERIES TRUST
Entity Central Index Key	0000751656
Entity Inv Company Type	N-1A
Amendment Flag	false
Document Creation Date	Jul. 27, 2023
Document Effective Date	Jul. 28, 2023
Prospectus Date	Jul. 28, 2023
MFS Alabama Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MFALX
MFS Alabama Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBABX
MFS Alabama Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MLALX
MFS Alabama Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPOLX
MFS Arkansas Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MFARX
MFS Arkansas Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBARX
MFS Arkansas Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MARLX
MFS Arkansas Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPRAX
MFS California Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MCFTX
MFS California Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBCAX
MFS California Municipal Bond Fund \| C
Prospectus:
Trading Symbol	MCCAX
MFS California Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MCAVX
MFS California Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPOAX
MFS Georgia Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MMGAX
MFS Georgia Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBGAX
MFS Georgia Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MGATX
MFS Georgia Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPGOX
MFS Maryland Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MFSMX
MFS Maryland Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBMDX
MFS Maryland Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MMDIX
MFS Maryland Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPMDX
MFS Massachusetts Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MFSSX
MFS Massachusetts Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBMAX
MFS Massachusetts Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MTALX
MFS Massachusetts Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPMAX
MFS Mississippi Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MISSX
MFS Mississippi Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBMSX
MFS Mississippi Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MMSTX
MFS Mississippi Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPMSX
MFS Municipal Income Fund \| A
Prospectus:
Trading Symbol	MFIAX
MFS Municipal Income Fund \| B
Prospectus:
Trading Symbol	MMIBX
MFS Municipal Income Fund \| C
Prospectus:
Trading Symbol	MMICX
MFS Municipal Income Fund \| I
Prospectus:
Trading Symbol	MIMIX
MFS Municipal Income Fund \| R6
Prospectus:
Trading Symbol	MPMNX
MFS Municipal Intermediate Fund \| Class C
Prospectus:
Trading Symbol	MIUCX
MFS Municipal Intermediate Fund \| Class A
Prospectus:
Trading Symbol	MIUAX
MFS Municipal Intermediate Fund \| Class I
Prospectus:
Trading Symbol	MIUIX
MFS Municipal Intermediate Fund \| Class R6
Prospectus:
Trading Symbol	MIURX
MFS New York Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MSNYX
MFS New York Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBNYX
MFS New York Municipal Bond Fund \| C
Prospectus:
Trading Symbol	MCNYX
MFS New York Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MNYLX
MFS New York Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPNYX
MFS North Carolina Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MSNCX
MFS North Carolina Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBNCX
MFS North Carolina Municipal Bond Fund \| C
Prospectus:
Trading Symbol	MCNCX
MFS North Carolina Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MNCLX
MFS North Carolina Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPNCX
MFS Pennsylvania Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MFPAX
MFS Pennsylvania Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBPAX
MFS Pennsylvania Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MPALX
MFS Pennsylvania Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPPAX
MFS South Carolina Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MFSCX
MFS South Carolina Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBSCX
MFS South Carolina Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MTSCX
MFS South Carolina Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPOCX
MFS Virginia Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MSVAX
MFS Virginia Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBVAX
MFS Virginia Municipal Bond Fund \| C
Prospectus:
Trading Symbol	MVACX
MFS Virginia Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MIVAX
MFS Virginia Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPVOX
MFS West Virginia Municipal Bond Fund \| A
Prospectus:
Trading Symbol	MFWVX
MFS West Virginia Municipal Bond Fund \| B
Prospectus:
Trading Symbol	MBWVX
MFS West Virginia Municipal Bond Fund \| I
Prospectus:
Trading Symbol	MWVIX
MFS West Virginia Municipal Bond Fund \| R6
Prospectus:
Trading Symbol	MPWVX
A1 & B1 Prospectus \| MFS Municipal Income Fund \| A1
Prospectus:
Trading Symbol	MMIDX
A1 & B1 Prospectus \| MFS Municipal Income Fund \| B1
Prospectus:
Trading Symbol	MMIGX

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The date the document was made available and submitted, in YYYY-MM-DD format. The date of submission, date of acceptance by the recipient, and the document effective date are all potentially different.

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The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The date of the prospectus.

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