diff --git a/runtime/ftplugin/wast.vim b/runtime/ftplugin/wat.vim
similarity index 93%
rename from runtime/ftplugin/wast.vim
rename to runtime/ftplugin/wat.vim
index 0d9e98d37a..35d2d6a322 100644
--- a/runtime/ftplugin/wast.vim
+++ b/runtime/ftplugin/wat.vim
@@ -1,7 +1,7 @@
 " Vim filetype plugin file
 " Language:     WebAssembly
 " Maintainer:   rhysd <lin90162@yahoo.co.jp>
-" Last Change:  Jul 29, 2018
+" Last Change:  Nov 14, 2023
 " For bugs, patches and license go to https://github.com/rhysd/vim-wasm
 
 if exists("b:did_ftplugin")
diff --git a/runtime/indent/wast.vim b/runtime/indent/wat.vim
similarity index 93%
rename from runtime/indent/wast.vim
rename to runtime/indent/wat.vim
index 1be234b6e9..08997f1a98 100644
--- a/runtime/indent/wast.vim
+++ b/runtime/indent/wat.vim
@@ -1,7 +1,7 @@
 " Vim indent file
 " Language:     WebAssembly
 " Maintainer:   rhysd <lin90162@yahoo.co.jp>
-" Last Change:  Jul 29, 2018
+" Last Change:  Nov 14, 2023
 " For bugs, patches and license go to https://github.com/rhysd/vim-wasm
 
 if exists("b:did_indent")
diff --git a/runtime/lua/vim/filetype.lua b/runtime/lua/vim/filetype.lua
index aae63af132..217f673b5e 100644
--- a/runtime/lua/vim/filetype.lua
+++ b/runtime/lua/vim/filetype.lua
@@ -1074,7 +1074,7 @@ local extension = {
   wrl = 'vrml',
   vroom = 'vroom',
   vue = 'vue',
-  wast = 'wast',
+  wast = 'wat',
   wat = 'wat',
   wdl = 'wdl',
   wm = 'webmacro',
diff --git a/runtime/makemenu.vim b/runtime/makemenu.vim
index 8eea49d711..5d288e2f40 100644
--- a/runtime/makemenu.vim
+++ b/runtime/makemenu.vim
@@ -649,7 +649,7 @@ SynMenu UV.VSE\ JCL:vsejcl
 SynMenu WXYZ.WEB.CWEB:cweb
 SynMenu WXYZ.WEB.WEB:web
 SynMenu WXYZ.WEB.WEB\ Changes:change
-SynMenu WXYZ.WebAssembly:wast
+SynMenu WXYZ.WebAssembly:wat
 SynMenu WXYZ.Webmacro:webmacro
 SynMenu WXYZ.Website\ MetaLanguage:wml
 SynMenu WXYZ.wDiff:wdiff
diff --git a/runtime/synmenu.vim b/runtime/synmenu.vim
index fec5cc4b06..43aae6f88b 100644
--- a/runtime/synmenu.vim
+++ b/runtime/synmenu.vim
@@ -623,7 +623,7 @@ an 50.160.330 &Syntax.UV.VSE\ JCL :cal SetSyn("vsejcl")<CR>
 an 50.170.100 &Syntax.WXYZ.WEB.CWEB :cal SetSyn("cweb")<CR>
 an 50.170.110 &Syntax.WXYZ.WEB.WEB :cal SetSyn("web")<CR>
 an 50.170.120 &Syntax.WXYZ.WEB.WEB\ Changes :cal SetSyn("change")<CR>
-an 50.170.130 &Syntax.WXYZ.WebAssembly :cal SetSyn("wast")<CR>
+an 50.170.130 &Syntax.WXYZ.WebAssembly :cal SetSyn("wat")<CR>
 an 50.170.140 &Syntax.WXYZ.Webmacro :cal SetSyn("webmacro")<CR>
 an 50.170.150 &Syntax.WXYZ.Website\ MetaLanguage :cal SetSyn("wml")<CR>
 an 50.170.170 &Syntax.WXYZ.wDiff :cal SetSyn("wdiff")<CR>
diff --git a/runtime/syntax/wast.vim b/runtime/syntax/wast.vim
deleted file mode 100644
index 113d65c5a1..0000000000
--- a/runtime/syntax/wast.vim
+++ /dev/null
@@ -1,97 +0,0 @@
-" Vim syntax file
-" Language:     WebAssembly
-" Maintainer:   rhysd <lin90162@yahoo.co.jp>
-" Last Change:  Aug 7, 2023
-" For bugs, patches and license go to https://github.com/rhysd/vim-wasm
-
-if exists("b:current_syntax")
-    finish
-endif
-
-let s:cpo_save = &cpo
-set cpo&vim
-
-syn cluster wastNotTop contains=wastModule,wastInstWithType,wastInstGetSet,wastInstGeneral,wastParamInst,wastControlInst,wastSimdInst,wastString,wastNamedVar,wastUnnamedVar,wastFloat,wastNumber,wastComment,wastList,wastType
-
-" Instructions
-" https://webassembly.github.io/spec/core/text/instructions.html
-" Note: memarg (align=,offset=) can be added to memory instructions
-syn match   wastInstWithType  "\%((\s*\)\@<=\<\%(i32\|i64\|f32\|f64\|memory\)\.[[:alnum:]_]\+\%(/\%(i32\|i64\|f32\|f64\)\)\=\>\%(\s\+\%(align\|offset\)=\)\=" contained display
-syn match   wastInstGeneral   "\%((\s*\)\@<=\<[[:alnum:]_]\+\>" contained display
-syn match   wastInstGetSet    "\%((\s*\)\@<=\<\%(local\|global\)\.\%(get\|set\)\>" contained display
-" https://webassembly.github.io/spec/core/text/instructions.html#control-instructions
-syn match   wastControlInst   "\%((\s*\)\@<=\<\%(block\|end\|loop\|if\|then\|else\|unreachable\|nop\|br\|br_if\|br_table\|return\|call\|call_indirect\)\>" contained display
-" https://webassembly.github.io/spec/core/text/instructions.html#parametric-instructions
-syn match   wastParamInst     "\%((\s*\)\@<=\<\%(drop\|select\)\>" contained display
-" SIMD instructions
-" https://webassembly.github.io/simd/core/text/instructions.html#simd-instructions
-syn match   wastSimdInst      "\<\%(v128\|i8x16\|i16x8\|i32x4\|i64x2\|f32x4\|f64x2)\)\.[[:alnum:]_]\+\%(\s\+\%(i8x16\|i16x8\|i32x4\|i64x2\|f32x4\|f64x2\)\)\=\>" contained display
-
-" Identifiers
-" https://webassembly.github.io/spec/core/text/values.html#text-id
-syn match   wastNamedVar      "$\+[[:alnum:]!#$%&'∗./:=><?@\\^_`~+-]*" contained contains=wastEscapeUtf8
-syn match   wastUnnamedVar    "$\+\d\+[[:alnum:]!#$%&'∗./:=><?@\\^_`~+-]\@!" contained display
-" Presuming the source text is itself encoded correctly, strings that do not
-" contain any uses of hexadecimal byte escapes are always valid names.
-" https://webassembly.github.io/spec/core/text/values.html#names
-syn match   wastEscapedUtf8   "\\\x\{1,6}" contained containedin=wastNamedVar display
-
-" String literals
-" https://webassembly.github.io/spec/core/text/values.html#strings
-syn region  wastString        start=+"+ skip=+\\\\\|\\"+ end=+"+ contained contains=wastStringSpecial
-syn match   wastStringSpecial "\\\x\x\|\\[tnr'\\\"]\|\\u\x\+" contained containedin=wastString display
-
-" Float literals
-" https://webassembly.github.io/spec/core/text/values.html#floating-point
-syn match   wastFloat         "\<-\=\d\%(_\=\d\)*\%(\.\d\%(_\=\d\)*\)\=\%([eE][-+]\=\d\%(_\=\d\)*\)\=" display contained
-syn match   wastFloat         "\<-\=0x\x\%(_\=\x\)*\%(\.\x\%(_\=\x\)*\)\=\%([pP][-+]\=\d\%(_\=\d\)*\)\=" display contained
-syn keyword wastFloat         inf nan contained
-syn match   wastFloat         "nan:0x\x\%(_\=\x\)*" display contained
-
-" Integer literals
-" https://webassembly.github.io/spec/core/text/values.html#integers
-syn match   wastNumber        "\<-\=\d\%(_\=\d\)*\>" display contained
-syn match   wastNumber        "\<-\=0x\x\%(_\=\x\)*\>" display contained
-
-" Comments
-" https://webassembly.github.io/spec/core/text/lexical.html#comments
-syn region  wastComment       start=";;" end="$"
-syn region  wastComment       start="(;;\@!" end=";)"
-
-syn region  wastList          matchgroup=wastListDelimiter start="(;\@!" matchgroup=wastListDelimiter end=";\@<!)" contains=@wastNotTop
-
-" Types
-" https://webassembly.github.io/spec/core/text/types.html
-" Note: `mut` was changed to `const`/`var` at Wasm 2.0
-syn keyword wastType          i64 i32 f64 f32 param result funcref func externref extern mut v128 const var contained
-syn match   wastType          "\%((\_s*\)\@<=func\%(\_s*[()]\)\@=" display contained
-
-" Modules
-" https://webassembly.github.io/spec/core/text/modules.html
-syn keyword wastModule        module type export import table memory global data elem contained
-syn match   wastModule        "\%((\_s*\)\@<=func\%(\_s\+\$\)\@=" display contained
-
-syn sync maxlines=100
-
-hi def link wastModule        PreProc
-hi def link wastListDelimiter Delimiter
-hi def link wastInstWithType  Operator
-hi def link wastInstGetSet    Operator
-hi def link wastInstGeneral   Operator
-hi def link wastControlInst   Statement
-hi def link wastSimdInst      Operator
-hi def link wastParamInst     Conditional
-hi def link wastString        String
-hi def link wastStringSpecial Special
-hi def link wastNamedVar      Identifier
-hi def link wastUnnamedVar    PreProc
-hi def link wastFloat         Float
-hi def link wastNumber        Number
-hi def link wastComment       Comment
-hi def link wastType          Type
-hi def link wastEscapedUtf8   Special
-
-let b:current_syntax = "wast"
-
-let &cpo = s:cpo_save
-unlet s:cpo_save
diff --git a/runtime/syntax/wat.vim b/runtime/syntax/wat.vim
new file mode 100644
index 0000000000..a6b926be98
--- /dev/null
+++ b/runtime/syntax/wat.vim
@@ -0,0 +1,97 @@
+" Vim syntax file
+" Language:     WebAssembly
+" Maintainer:   rhysd <lin90162@yahoo.co.jp>
+" Last Change:  Nov 14, 2023
+" For bugs, patches and license go to https://github.com/rhysd/vim-wasm
+
+if exists("b:current_syntax")
+    finish
+endif
+
+let s:cpo_save = &cpo
+set cpo&vim
+
+syn cluster watNotTop contains=watModule,watInstWithType,watInstGetSet,watInstGeneral,watParamInst,watControlInst,watSimdInst,watString,watNamedVar,watUnnamedVar,watFloat,watNumber,watComment,watList,watType
+
+" Instructions
+" https://webassembly.github.io/spec/core/text/instructions.html
+" Note: memarg (align=,offset=) can be added to memory instructions
+syn match   watInstWithType  "\%((\s*\)\@<=\<\%(i32\|i64\|f32\|f64\|memory\)\.[[:alnum:]_]\+\%(/\%(i32\|i64\|f32\|f64\)\)\=\>\%(\s\+\%(align\|offset\)=\)\=" contained display
+syn match   watInstGeneral   "\%((\s*\)\@<=\<[[:alnum:]_]\+\>" contained display
+syn match   watInstGetSet    "\%((\s*\)\@<=\<\%(local\|global\)\.\%(get\|set\)\>" contained display
+" https://webassembly.github.io/spec/core/text/instructions.html#control-instructions
+syn match   watControlInst   "\%((\s*\)\@<=\<\%(block\|end\|loop\|if\|then\|else\|unreachable\|nop\|br\|br_if\|br_table\|return\|call\|call_indirect\)\>" contained display
+" https://webassembly.github.io/spec/core/text/instructions.html#parametric-instructions
+syn match   watParamInst     "\%((\s*\)\@<=\<\%(drop\|select\)\>" contained display
+" SIMD instructions
+" https://webassembly.github.io/simd/core/text/instructions.html#simd-instructions
+syn match   watSimdInst      "\<\%(v128\|i8x16\|i16x8\|i32x4\|i64x2\|f32x4\|f64x2)\)\.[[:alnum:]_]\+\%(\s\+\%(i8x16\|i16x8\|i32x4\|i64x2\|f32x4\|f64x2\)\)\=\>" contained display
+
+" Identifiers
+" https://webassembly.github.io/spec/core/text/values.html#text-id
+syn match   watNamedVar      "$\+[[:alnum:]!#$%&'∗./:=><?@\\^_`~+-]*" contained contains=watEscapeUtf8
+syn match   watUnnamedVar    "$\+\d\+[[:alnum:]!#$%&'∗./:=><?@\\^_`~+-]\@!" contained display
+" Presuming the source text is itself encoded correctly, strings that do not
+" contain any uses of hexadecimal byte escapes are always valid names.
+" https://webassembly.github.io/spec/core/text/values.html#names
+syn match   watEscapedUtf8   "\\\x\{1,6}" contained containedin=watNamedVar display
+
+" String literals
+" https://webassembly.github.io/spec/core/text/values.html#strings
+syn region  watString        start=+"+ skip=+\\\\\|\\"+ end=+"+ contained contains=watStringSpecial
+syn match   watStringSpecial "\\\x\x\|\\[tnr'\\\"]\|\\u\x\+" contained containedin=watString display
+
+" Float literals
+" https://webassembly.github.io/spec/core/text/values.html#floating-point
+syn match   watFloat         "\<-\=\d\%(_\=\d\)*\%(\.\d\%(_\=\d\)*\)\=\%([eE][-+]\=\d\%(_\=\d\)*\)\=" display contained
+syn match   watFloat         "\<-\=0x\x\%(_\=\x\)*\%(\.\x\%(_\=\x\)*\)\=\%([pP][-+]\=\d\%(_\=\d\)*\)\=" display contained
+syn keyword watFloat         inf nan contained
+syn match   watFloat         "nan:0x\x\%(_\=\x\)*" display contained
+
+" Integer literals
+" https://webassembly.github.io/spec/core/text/values.html#integers
+syn match   watNumber        "\<-\=\d\%(_\=\d\)*\>" display contained
+syn match   watNumber        "\<-\=0x\x\%(_\=\x\)*\>" display contained
+
+" Comments
+" https://webassembly.github.io/spec/core/text/lexical.html#comments
+syn region  watComment       start=";;" end="$"
+syn region  watComment       start="(;;\@!" end=";)"
+
+syn region  watList          matchgroup=watListDelimiter start="(;\@!" matchgroup=watListDelimiter end=";\@<!)" contains=@watNotTop
+
+" Types
+" https://webassembly.github.io/spec/core/text/types.html
+" Note: `mut` was changed to `const`/`var` at Wasm 2.0
+syn keyword watType          i64 i32 f64 f32 param result funcref func externref extern mut v128 const var contained
+syn match   watType          "\%((\_s*\)\@<=func\%(\_s*[()]\)\@=" display contained
+
+" Modules
+" https://webassembly.github.io/spec/core/text/modules.html
+syn keyword watModule        module type export import table memory global data elem contained
+syn match   watModule        "\%((\_s*\)\@<=func\%(\_s\+\$\)\@=" display contained
+
+syn sync maxlines=100
+
+hi def link watModule        PreProc
+hi def link watListDelimiter Delimiter
+hi def link watInstWithType  Operator
+hi def link watInstGetSet    Operator
+hi def link watInstGeneral   Operator
+hi def link watControlInst   Statement
+hi def link watSimdInst      Operator
+hi def link watParamInst     Conditional
+hi def link watString        String
+hi def link watStringSpecial Special
+hi def link watNamedVar      Identifier
+hi def link watUnnamedVar    PreProc
+hi def link watFloat         Float
+hi def link watNumber        Number
+hi def link watComment       Comment
+hi def link watType          Type
+hi def link watEscapedUtf8   Special
+
+let b:current_syntax = "wat"
+
+let &cpo = s:cpo_save
+unlet s:cpo_save
diff --git a/test/old/testdir/test_filetype.vim b/test/old/testdir/test_filetype.vim
index d0361d6a87..b45895d608 100644
--- a/test/old/testdir/test_filetype.vim
+++ b/test/old/testdir/test_filetype.vim
@@ -708,8 +708,7 @@ func s:GetFilenameChecks() abort
     \ 'vrml': ['file.wrl'],
     \ 'vroom': ['file.vroom'],
     \ 'vue': ['file.vue'],
-    \ 'wat': ['file.wat'],
-    \ 'wast': ['file.wast'],
+    \ 'wat': ['file.wat', 'file.wast'],
     \ 'wdl': ['file.wdl'],
     \ 'webmacro': ['file.wm'],
     \ 'wget': ['.wgetrc', 'wgetrc'],