diff --git a/src/TimeZones.jl b/src/TimeZones.jl
index 4b704d84..30db41e4 100644
--- a/src/TimeZones.jl
+++ b/src/TimeZones.jl
@@ -54,15 +54,8 @@ function __init__()
     # TimeZones.jl is loaded by `deps/build.jl` as we have yet to compile the tzdata.
     isdir(_COMPILED_DIR[]) && _reload_cache(_COMPILED_DIR[])
 
-    # Base extension needs to happen everytime the module is loaded (issue #24)
-    Dates.CONVERSION_SPECIFIERS['z'] = TimeZone
-    Dates.CONVERSION_SPECIFIERS['Z'] = TimeZone
-    Dates.CONVERSION_DEFAULTS[TimeZone] = ""
-    Dates.CONVERSION_TRANSLATIONS[ZonedDateTime] = (
-        Year, Month, Day, Hour, Minute, Second, Millisecond, TimeZone,
-    )
-
-    global ISOZonedDateTimeFormat = DateFormat("yyyy-mm-ddTHH:MM:SS.ssszzz")
+    # Dates extension needs to happen everytime the module is loaded (issue #24)
+    init_dates_extension()
 end
 
 include("utils.jl")
diff --git a/src/parse.jl b/src/parse.jl
index 8d4393cd..2ef08fd0 100644
--- a/src/parse.jl
+++ b/src/parse.jl
@@ -1,6 +1,22 @@
 using Dates: DateFormat, DatePart, min_width, max_width, tryparsenext_base10
 using TimeZones.TZData: MIN_YEAR, MAX_YEAR
 
+function init_dates_extension()
+    Dates.CONVERSION_SPECIFIERS['z'] = TimeZone
+    Dates.CONVERSION_SPECIFIERS['Z'] = TimeZone
+    Dates.CONVERSION_DEFAULTS[TimeZone] = ""
+    Dates.CONVERSION_TRANSLATIONS[ZonedDateTime] = (
+        Year, Month, Day, Hour, Minute, Second, Millisecond, TimeZone,
+    )
+end
+
+const ISOZonedDateTimeFormat = let
+    init_dates_extension()
+    DateFormat("yyyy-mm-ddTHH:MM:SS.ssszzz")
+end
+
+Dates.default_format(::Type{ZonedDateTime}) = ISOZonedDateTimeFormat
+
 function tryparsenext_fixedtz(str, i, len, min_width::Int=1, max_width::Int=0)
     i == len && str[i] === 'Z' && return ("Z", i+1)
 
@@ -81,8 +97,6 @@ function Dates.format(io::IO, d::DatePart{'Z'}, zdt, locale)
     write(io, string(zdt.zone))  # In most cases will be an abbreviation.
 end
 
-# Note: ISOZonedDateTimeFormat is defined in the module __init__ which means that this
-# function can not be called from within this module. TODO: Ignore linting for this line
 function ZonedDateTime(str::AbstractString, df::DateFormat=ISOZonedDateTimeFormat)
     try
         parse(ZonedDateTime, str, df)
@@ -101,8 +115,6 @@ function ZonedDateTime(str::AbstractString, format::AbstractString; locale::Abst
     ZonedDateTime(str, DateFormat(format, locale))
 end
 
-Dates.default_format(::Type{ZonedDateTime}) = ISOZonedDateTimeFormat
-
 
 """
     _parsesub_tzabbr(str, [i, len]) -> Union{Tuple{AbstractString, Integer}, Exception}